| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854 | <!doctype html><html>  <head>    <title>CodeMirror: User Manual</title>    <link rel="stylesheet" type="text/css" href="http://fonts.googleapis.com/css?family=Droid+Sans|Droid+Sans:bold"/>    <link rel="stylesheet" type="text/css" href="css/docs.css"/>    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>    <style>dl dl {margin: 0;}</style>  </head>  <body><h1><span class="logo-braces">{ }</span> <a href="http://codemirror.net/">CodeMirror</a></h1><pre class="grey"><img src="css/baboon.png" class="logo" alt="logo"/>/* User manual and   reference guide */</pre><div class="clear"><div class="leftbig blk">    <h2 id="overview">Overview</h2>    <p>CodeMirror is a code-editor component that can be embedded in    Web pages. It provides <em>only</em> the editor component, no    accompanying buttons    (see <a href="http://www.octolabs.com/javascripts/codemirror-ui/">CodeMirror    UI</a> for a drop-in button bar), auto-completion, or other IDE    functionality. It does provide a rich API on top of which such    functionality can be straightforwardly implemented.</p>    <p>CodeMirror works with language-specific modes. Modes are    JavaScript programs that help color (and optionally indent) text    written in a given language. The distribution comes with a few    modes (see the <code>mode/</code> directory), and it isn't hard    to <a href="#modeapi">write new ones</a> for other languages.</p>    <h2 id="usage">Basic Usage</h2>    <p>The easiest way to use CodeMirror is to simply load the script    and style sheet found under <code>lib/</code> in the distribution,    plus a mode script from one of the <code>mode/</code> directories    and a theme stylesheet from <code>theme/</code>. (See    also <a href="compress.html">the compresion helper</a>.) For    example:</p>    <pre><script src="lib/codemirror.js"></script><link rel="stylesheet" href="lib/codemirror.css"><script src="mode/javascript/javascript.js"></script><link rel="stylesheet" href="theme/default.css"></pre>    <p>(If you use a them other than <code>default.css</code>, you    also have to specify the    <a href="#option_theme"><code>theme</code></a> option.) Having    done this, an editor instance can be created like this:</p>    <pre>var myCodeMirror = CodeMirror(document.body);</pre>    <p>The editor will be appended to the document body, will start    empty, and will use the mode that we loaded. To have more control    over the new editor, a configuration object can be passed    to <code>CodeMirror</code> as a second argument:</p>    <pre>var myCodeMirror = CodeMirror(document.body, {  value: "function myScript(){return 100;}\n",  mode:  "javascript"});</pre>    <p>This will initialize the editor with a piece of code already in    it, and explicitly tell it to use the JavaScript mode (which is    useful when multiple modes are loaded).    See <a href="#config">below</a> for a full discussion of the    configuration options that CodeMirror accepts.</p>    <p>In cases where you don't want to append the editor to an    element, and need more control over the way it is inserted, the    first argument to the <code>CodeMirror</code> function can also    be a function that, when given a DOM element, inserts it into the    document somewhere. This could be used to, for example, replace a    textarea with a real editor:</p>    <pre>var myCodeMirror = CodeMirror(function(elt) {  myTextArea.parentNode.replaceChild(elt, myTextArea);}, {value: myTextArea.value});</pre>    <p>However, for this use case, which is a common way to use    CodeMirror, the library provides a much more powerful    shortcut:</p>    <pre>var myCodeMirror = CodeMirror.fromTextArea(myTextArea);</pre>    <p>This will, among other things, ensure that the textarea's value    is updated when the form (if it is part of a form) is submitted.    See the <a href="#fromTextArea">API reference</a> for a full    description of this method.</p>    <h2 id="config">Configuration</h2>    <p>Both the <code>CodeMirror</code> function and    its <code>fromTextArea</code> method take as second (optional)    argument an object containing configuration options. Any option    not supplied like this will be taken    from <code>CodeMirror.defaults</code>, an object containing the    default options. You can update this object to change the defaults    on your page.</p>    <p>Options are not checked in any way, so setting bogus option    values is bound to lead to odd errors.</p>    <p><em>Note:</em> CodeMirror    2 <a href="internals.html#summary">does not support</a>    line-wrapping. I would have very much liked to support it, but it    combines extremely poorly with the way the editor is    implemented.</p>    <p>These are the supported options:</p>    <dl>      <dt id="option_value"><code>value (string)</code></dt>      <dd>The starting value of the editor.</dd>      <dt id="option_mode"><code>mode (string or object)</code></dt>      <dd>The mode to use. When not given, this will default to the      first mode that was loaded. It may be a string, which either      simply names the mode or is      a <a href="http://en.wikipedia.org/wiki/MIME">MIME</a> type      associated with the mode. Alternatively, it may be an object      containing configuration options for the mode, with      a <code>name</code> property that names the mode (for      example <code>{name: "javascript", json: true}</code>). The demo      pages for each mode contain information about what configuration      parameters the mode supports. You can ask CodeMirror which modes      and MIME types are loaded with      the <code>CodeMirror.listModes</code>      and <code>CodeMirror.listMIMEs</code> functions.</dd>      <dt id="option_theme"><code>theme (string)</code></dt>      <dd>The theme to style the editor with. You must make sure the      CSS file defining the corresponding <code>.cm-s-[name]</code>      styles is loaded (see      the <a href="theme/"><code>theme</code></a> directory in the      distribution).</dd>      <dt id="option_indentUnit"><code>indentUnit (integer)</code></dt>      <dd>How many spaces a block (whatever that means in the edited      language) should be indented. The default is 2.</dd>      <dt id="option_indentWithTabs"><code>indentWithTabs (boolean)</code></dt>      <dd>Whether, when indenting, the first N*8 spaces should be      replaced by N tabs. Default is false.</dd>      <dt id="option_tabMode"><code>tabMode (string)</code></dt>      <dd>Determines what happens when the user presses the tab key.      Must be one of the following:        <dl>          <dt><code>"classic" (the default)</code></dt>          <dd>When nothing is selected, insert a tab. Otherwise,          behave like the <code>"shift"</code> mode. (When shift is          held, this behaves like the <code>"indent"</code> mode.)</dd>          <dt><code>"shift"</code></dt>          <dd>Indent all selected lines by          one <a href="#option_indentUnit"><code>indentUnit</code></a>.          If shift was held while pressing tab, un-indent all selected          lines one unit.</dd>          <dt><code>"indent"</code></dt>          <dd>Indent the line the 'correctly', based on its syntactic          context. Only works if the          mode <a href="#indent">supports</a> it.</dd>          <dt><code>"default"</code></dt>          <dd>Do not capture tab presses, let the browser apply its          default behaviour (which usually means it skips to the next          control).</dd>        </dl></dd>      <dt id="option_enterMode"><code>enterMode (string)</code></dt>      <dd>Determines whether and how new lines are indented when the      enter key is pressed. The following modes are supported:        <dl>          <dt><code>"indent" (the default)</code></dt>          <dd>Use the mode's indentation rules to give the new line          the correct indentation.</dd>          <dt><code>"keep"</code></dt>          <dd>Indent the line the same as the previous line.</dd>          <dt><code>"flat"</code></dt>          <dd>Do not indent the new line.</dd>        </dl></dd>      <dt id="option_electricChars"><code>electricChars (boolean)</code></dt>      <dd>Configures whether the editor should re-indent the current      line when a character is typed that might change its proper      indentation (only works if the mode supports indentation).      Default is true.</dd>      <dt id="option_lineNumbers"><code>lineNumbers (boolean)</code></dt>      <dd>Whether to show line numbers to the left of the editor.</dd>      <dt id="option_firstLineNumber"><code>firstLineNumber (integer)</code></dt>      <dd>At which number to start counting lines. Default is 1.</dd>      <dt id="option_gutter"><code>gutter (boolean)</code></dt>      <dd>Can be used to force a 'gutter' (empty space on the left of      the editor) to be shown even when no line numbers are active.      This is useful for setting <a href="#setMarker">markers</a>.</dd>      <dt id="option_readOnly"><code>readOnly (boolean)</code></dt>      <dd>This disables editing of the editor content by the user.      (Changes through API functions will still be possible.) If you      also want to disable the cursor, use <code>"nocursor"</code> as      a value for this option, instead of <code>true</code>.</dd>      <dt id="option_onChange"><code>onChange (function)</code></dt>      <dd>When given, this function will be called every time the      content of the editor is changed. It will be given the editor      instance as only argument.</dd>      <dt id="option_onCursorActivity"><code>onCursorActivity (function)</code></dt>      <dd>Like <code>onChange</code>, but will also be called when the      cursor moves without any changes being made.</dd>      <dt id="option_onGutterClick"><code>onGutterClick (function)</code></dt>      <dd>When given, will be called whenever the editor gutter (the      line-number area) is clicked. Will be given the editor instance      as first argument, and the (zero-based) number of the line that      was clicked as second argument.</dd>      <dt id="option_onFocus"><code>onFocus, onBlur (function)</code></dt>      <dd>The given functions will be called whenever the editor is      focused or unfocused.</dd>      <dt id="option_onScroll"><code>onScroll (function)</code></dt>      <dd>When given, will be called whenever the editor is      scrolled.</dd>      <dt id="option_onHighlightComplete"><code>onHighlightComplete (function)</code></dt>      <dd>Whenever the editor's content has been fully highlighted,      this function (if given) will be called. It'll be given a single      argument, the editor instance.</dd>      <dt id="option_matchBrackets"><code>matchBrackets (boolean)</code></dt>      <dd>Determines whether brackets are matched whenever the cursor      is moved next to a bracket.</dd>      <dt id="option_workTime"><code>workTime, workDelay (number)</code></dt>      <dd>Highlighting is done by a pseudo background-thread that will      work for <code>workTime</code> milliseconds, and then use      timeout to sleep for <code>workDelay</code> milliseconds. The      defaults are 200 and 300, you can change these options to make      the highlighting more or less aggressive.</dd>      <dt id="option_undoDepth"><code>undoDepth (integer)</code></dt>      <dd>The maximum number of undo levels that the editor stores.      Defaults to 40.</dd>      <dt id="option_tabindex"><code>tabindex (integer)</code></dt>      <dd>The <a href="http://www.w3.org/TR/html401/interact/forms.html#adef-tabindex">tab      index</a> to assign to the editor. If not given, no tab index      will be assigned.</dd>      <dt id="option_document"><code>document (DOM document)</code></dt>      <dd>Use this if you want to display the editor in another DOM.      By default it will use the global <code>document</code>      object.</dd>      <dt id="option_onKeyEvent"><code>onKeyEvent (function)</code></dt>      <dd>This provides a rather low-level hook into CodeMirror's key      handling. If provided, this function will be called on      every <code>keydown</code>, <code>keyup</code>,      and <code>keypress</code> event that CodeMirror captures. It      will be passed two arguments, the editor instance and the key      event. This key event is pretty much the raw key event, except      that a <code>stop()</code> method is always added to it. You      could feed it to, for example, <code>jQuery.Event</code> to      further normalize it.<br>This function can inspect the key      event, and handle it if it wants to. It may return true to tell      CodeMirror to ignore the event. Be wary that, on some browsers,      stopping a <code>keydown</code> does not stop      the <code>keypress</code> from firing, whereas on others it      does. If you respond to an event, you should probably inspect      its <code>type</code> property and only do something when it      is <code>keydown</code> (or <code>keypress</code> for actions      that need character data).</dd>    </dl>    <h2 id="styling">Customized Styling</h2>    <p>Up to a certain extent, CodeMirror's look can be changed by    modifying style sheet files. The style sheets supplied by modes    simply provide the colors for that mode, and can be adapted in a    very straightforward way. To style the editor itself, it is    possible to alter or override the styles defined    in <a href="lib/codemirror.css"><code>codemirror.css</code></a>.</p>    <p>Some care must be taken there, since a lot of the rules in this    file are necessary to have CodeMirror function properly. Adjusting    colors should be safe, of course, and with some care a lot of    other things can be changed as well. The CSS classes defined in    this file serve the following roles:</p>    <dl>      <dt id="class_CodeMirror"><code>CodeMirror</code></dt>      <dd>The outer element of the editor. This should be used for      borders and positioning. Can also be used to set styles that      should hold for everything inside the editor (such as font      and font size), or to set a background.</dd>      <dt id="class_CodeMirror_scroll"><code>CodeMirror-scroll</code></dt>      <dd>This determines whether the editor scrolls (<code>overflow:      auto</code> + fixed height). By default, it does. Giving      this <code>height: auto; overflow: visible;</code> will cause      the editor to resize to fit its content.</dd>      <dt id="class_CodeMirror_focused"><code>CodeMirror-focused</code></dt>      <dd>Whenever the editor is focused, the top element gets this      class. This is used to hide the cursor and give the selection a      different color when the editor is not focused.</dd>      <dt id="class_CodeMirror_gutter"><code>CodeMirror-gutter</code></dt>      <dd>Use this for giving a background or a border to the editor      gutter. Don't set any padding here,      use <code>CodeMirror-gutter-text</code> for that. By default,      the gutter is 'fluid', meaning it will adjust its width to the      maximum line number or line marker width. You can also set a      fixed width if you want.</dd>      <dt id="class_CodeMirror_gutter_text"><code>CodeMirror-gutter-text</code></dt>      <dd>Used to style the actual line numbers. For the numbers to      line up, you must make sure that the font in the gutter is the      same as the one in the rest of the editor, so you should      probably only set font style and size in      the <code>CodeMirror</code> class.</dd>      <dt id="class_CodeMirror_lines"><code>CodeMirror-lines</code></dt>      <dd>The visible lines. If this has vertical      padding, <code>CodeMirror-gutter</code> should have the same      padding.</dd>      <dt id="class_CodeMirror_cursor"><code>CodeMirror-cursor</code></dt>      <dd>The cursor is a block element that is absolutely positioned.      You can make it look whichever way you want.</dd>      <dt id="class_CodeMirror_selected"><code>CodeMirror-selected</code></dt>      <dd>The selection is represented by <code>span</code> elements      with this class.</dd>      <dt id="class_CodeMirror_matchingbracket"><code>CodeMirror-matchingbracket</code>,        <code>CodeMirror-nonmatchingbracket</code></dt>      <dd>These are used to style matched (or unmatched) brackets.</dd>    </dl>    <p>The actual lines, as well as the cursor, are represented    by <code>pre</code> elements. By default no text styling (such as    bold) that might change line height is applied. If you do want    such effects, you'll have to give <code>CodeMirror pre</code> a    fixed height. Also, you must still take care that character width    is constant.</p>    <p>If your page's style sheets do funky things to    all <code>div</code> or <code>pre</code> elements (you probably    shouldn't do that), you'll have to define rules to cancel these    effects out again for elements under the <code>CodeMirror</code>    class.</p>    <h2 id="api">Programming API</h2>    <p>A lot of CodeMirror features are only available through its API.    This has the disadvantage that you need to do work to enable them,    and the advantage that CodeMirror will fit seamlessly into your    application.</p>    <p>Whenever points in the document are represented, the API uses    objects with <code>line</code> and <code>ch</code> properties.    Both are zero-based. CodeMirror makes sure to 'clip' any positions    passed by client code so that they fit inside the document, so you    shouldn't worry too much about sanitizing your coordinates. If you    give <code>ch</code> a value of <code>null</code>, or don't    specify it, it will be replaced with the length of the specified    line.</p>    <dl>      <dt id="getValue"><code>getValue() → string</code></dt>      <dd>Get the current editor content.</dd>      <dt id="setValue"><code>setValue(string)</code></dt>      <dd>Set the editor content.</dd>      <dt id="getSelection"><code>getSelection() → string</code></dt>      <dd>Get the currently selected code.</dd>      <dt id="replaceSelection"><code>replaceSelection(string)</code></dt>      <dd>Replace the selection with the given string.</dd>      <dt id="focus"><code>focus()</code></dt>      <dd>Give the editor focus.</dd>      <dt id="setOption"><code>setOption(option, value)</code></dt>      <dd>Change the configuration of the editor. <code>option</code>      should the name of an <a href="#config">option</a>,      and <code>value</code> should be a valid value for that      option.</dd>      <dt id="getOption"><code>getOption(option) → value</code></dt>      <dd>Retrieves the current value of the given option for this      editor instance.</dd>      <dt id="cursorCoords"><code>cursorCoords(start) → object</code></dt>      <dd>Returns an <code>{x, y, yBot}</code> object containing the      coordinates of the cursor relative to the top-left corner of the      page. <code>yBot</code> is the coordinate of the bottom of the      cursor. <code>start</code> is a boolean indicating whether you      want the start or the end of the selection.</dd>      <dt id="charCoords"><code>charCoords(pos) → object</code></dt>      <dd>Like <code>cursorCoords</code>, but returns the position of      an arbitrary characters. <code>pos</code> should be      a <code>{line, ch}</code> object.</dd>      <dt id="coordsChar"><code>coordsChar(object) → pos</code></dt>      <dd>Given an <code>{x, y}</code> object (in page coordinates),      returns the <code>{line, ch}</code> position that corresponds to      it.</dd>      <dt id="undo"><code>undo()</code></dt>      <dd>Undo one edit (if any undo events are stored).</dd>      <dt id="redo"><code>redo()</code></dt>      <dd>Redo one undone edit.</dd>      <dt id="historySize"><code>historySize() → object</code></dt>      <dd>Returns an object with <code>{undo, redo}</code> properties,      both of which hold integers, indicating the amount of stored      undo and redo operations.</dd>      <dt id="indentLine"><code>indentLine(line)</code></dt>      <dd>Reset the given line's indentation to the indentation      prescribed by the mode.</dd>      <dt id="getSearchCursor"><code>getSearchCursor(query, start, caseFold) → cursor</code></dt>      <dd>Used to implement search/replace      functionality. <code>query</code> can be a regular expression or      a string (only strings will match across lines—if they contain      newlines). <code>start</code> provides the starting position of      the search. It can be a <code>{line, ch}</code> object, or can      be left off to default to the start of the      document. <code>caseFold</code> is only relevant when matching a      string. It will cause the search to be case-insensitive. A      search cursor has the following methods:        <dl>          <dt><code>findNext(), findPrevious() → boolean</code></dt>          <dd>Search forward or backward from the current position.          The return value indicates whether a match was found. If          matching a regular expression, the return value will be the          array returned by the <code>match</code> method, in case you          want to extract matched groups.</dd>          <dt><code>from(), to() → object</code></dt>          <dd>These are only valid when the last call          to <code>findNext</code> or <code>findPrevious</code> did          not return false. They will return <code>{line, ch}</code>          objects pointing at the start and end of the match.</dd>          <dt><code>replace(text)</code></dt>          <dd>Replaces the currently found match with the given text          and adjusts the cursor position to reflect the          replacement.</dd>        </dl></dd>      <dt id="getTokenAt"><code>getTokenAt(pos) → object</code></dt>      <dd>Retrieves information about the token the current mode found      at the given position (a <code>{line, ch}</code> object). The      returned object has the following properties:      <dl>        <dt><code>start</code></dt><dd>The character (on the given line) at which the token starts.</dd>        <dt><code>end</code></dt><dd>The character at which the token ends.</dd>        <dt><code>string</code></dt><dd>The token's string.</dd>        <dt><code>className</code></dt><dd>The class the mode assigned        to the token. (Can be null when no class was assigned.)</dd>        <dt><code>state</code></dt><dd>The mode's state at the end of this token.</dd>      </dl></dd>      <dt id="markText"><code>markText(from, to, className) → function</code></dt>      <dd>Can be used to mark a range of text with a specific CSS      class name. <code>from</code> and <code>to</code> should      be <code>{line, ch}</code> objects. The method will return a      function that can be called to remove the marking.</dd>      <dt id="setMarker"><code>setMarker(line, text, className) → lineHandle</code></dt>      <dd>Add a gutter marker for the given line. Gutter markers are      shown in the line-number area (instead of the number for this      line). Both <code>text</code> and <code>className</code> are      optional. Setting <code>text</code> to a Unicode character like      ● tends to give a nice effect. To put a picture in the gutter,      set <code>text</code> to a space and <code>className</code> to      something that sets a background image. If you      specify <code>text</code>, the given text (which may contain      HTML) will, by default, replace the line number for that line.      If this is not what you want, you can include the      string <code>%N%</code> in the text, which will be replaced by      the line number.</dd>      <dt id="clearMarker"><code>clearMarker(line)</code></dt>      <dd>Clears a marker created      with <code>setMarker</code>. <code>line</code> can be either a      number or a handle returned by <code>setMarker</code> (since a      number may now refer to a different line if something was added      or deleted).</dd>      <dt id="setLineClass"><code>setLineClass(line, className) → lineHandle</code></dt>      <dd>Set a CSS class name for the given line. <code>line</code>      can be a number or a line handle (as returned      by <code>setMarker</code> or this function).      Pass <code>null</code> to clear the class for a line.</dd>      <dt id="lineInfo"><code>lineInfo(line) → object</code></dt>      <dd>Returns the line number, text content, and marker status of      the given line, which can be either a number or a handle      returned by <code>setMarker</code>. The returned object has the      structure <code>{line, text, markerText, markerClass}</code>.</dd>      <dt id="addWidget"><code>addWidget(pos, node, scrollIntoView)</code></dt>      <dd>Puts <code>node</code>, which should be an absolutely      positioned DOM node, into the editor, positioned right below the      given <code>{line, ch}</code> position.      When <code>scrollIntoView</code> is true, the editor will ensure      that the entire node is visible (if possible). To remove the      widget again, simply use DOM methods (move it somewhere else, or      call <code>removeChild</code> on its parent).</dd>      <dt id="matchBrackets"><code>matchBrackets()</code></dt>      <dd>Force matching-bracket-highlighting to happen.</dd>      <dt id="lineCount"><code>lineCount() → number</code></dt>      <dd>Get the number of lines in the editor.</dd>      <dt id="getCursor"><code>getCursor(start) → object</code></dt>      <dd><code>start</code> is a boolean indicating whether the start      or the end of the selection must be retrieved. If it is not      given, the current cursor pos, i.e. the side of the selection      that would move if you pressed an arrow key, is chosen.      A <code>{line, ch}</code> object will be returned.</dd>      <dt id="somethingSelected"><code>somethingSelected() → boolean</code></dt>      <dd>Return true if any text is selected.</dd>      <dt id="setCursor"><code>setCursor(pos)</code></dt>      <dd>Set the cursor position. You can either pass a      single <code>{line, ch}</code> object, or the line and the      character as two separate parameters.</dd>      <dt id="setSelection"><code>setSelection(start, end)</code></dt>      <dd>Set the selection range. <code>start</code>      and <code>end</code> should be <code>{line, ch}</code> objects.</dd>      <dt id="getLine"><code>getLine(n) → string</code></dt>      <dd>Get the content of line <code>n</code>.</dd>      <dt id="setLine"><code>setLine(n, text)</code></dt>      <dd>Set the content of line <code>n</code>.</dd>      <dt id="removeLine"><code>removeLine(n)</code></dt>      <dd>Remove the given line from the document.</dd>      <dt id="getRange"><code>getRange(from, to) → string</code></td>      <dd>Get the text between the given points in the editor, which      should be <code>{line, ch}</code> objects.</dd>      <dt id="replaceRange"><code>replaceRange(string, from, to)</code></dt>      <dd>Replace the part of the document between <code>from</code>      and <code>to</code> with the given string. <code>from</code>      and <code>to</code> must be <code>{line, ch}</code>      objects. <code>to</code> can be left off to simply insert the      string at position <code>from</code>.</dd>    </dl>    <p>The following are more low-level methods:</p>    <dl>      <dt id="operation"><code>operation(func) → result</code></dt>      <dd>CodeMirror internally buffers changes and only updates its      DOM structure after it has finished performing some operation.      If you need to perform a lot of operations on a CodeMirror      instance, you can call this method with a function argument. It      will call the function, buffering up all changes, and only doing      the expensive update after the function returns. This can be a      lot faster. The return value from this method will be the return      value of your function.</dd>      <dt id="refresh"><code>refresh()</code></dt>      <dd>If your code does something to change the size of the editor      element (window resizes are already listened for), or unhides      it, you should probably follow up by calling this method to      ensure CodeMirror is still looking as intended.</dd>      <dt id="getInputField"><code>getInputField() → textarea</code></dt>      <dd>Returns the hiden textarea used to read input.</dd>      <dt id="getWrapperElement"><code>getWrapperElement() → node</code></dt>      <dd>Returns the DOM node that represents the editor. Remove this      from your tree to delete an editor instance.</dd>      <dt id="getScrollerElement"><code>getScrollerElement() → node</code></dt>      <dd>Returns the DOM node that is responsible for the sizing and      the scrolling of the editor. You can change      the <code>height</code> and <code>width</code> styles of this      element to resize an editor. (You might have to call      the <a href="#refresh"><code>refresh</code></a> method      afterwards.)</dd>      <dt id="getStateAfter"><code>getStateAfter(line) → state</code></dt>      <dd>Returns the mode's parser state, if any, at the end of the      given line number. If no line number is given, the state at the      end of the document is returned. This can be useful for storing      parsing errors in the state, or getting other kinds of      contextual information for a line.</dd>    </dl>    <p id="fromTextArea">Finally, the <code>CodeMirror</code> object    itself has a method <code>fromTextArea</code>. This takes a    textarea DOM node as first argument and an optional configuration    object as second. It will replace the textarea with a CodeMirror    instance, and wire up the form of that textarea (if any) to make    sure the editor contents are put into the textarea when the form    is submitted. A CodeMirror instance created this way has two    additional methods:</p>    <dl>      <dt id="save"><code>save()</code></dt>      <dd>Copy the content of the editor into the textarea.</dd>      <dt id="toTextArea"><code>toTextArea()</code></dt>      <dd>Remove the editor, and restore the original textarea (with      the editor's current content).</dd>    </dl>    <p id="defineExtension">If you want define extra methods in terms    of the CodeMirror API, is it possible to    use <code>CodeMirror.defineExtension(name, value)</code>. This    will cause the given value (usually a method) to be added to all    CodeMirror instances created from then on.</p>    <h2 id="modeapi">Writing CodeMirror Modes</h2>    <p>Modes typically consist of a JavaScript file and a CSS file.    The CSS file (see, for    example <a href="mode/javascript/javascript.css"><code>javascript.css</code></a>)    defines the classes that will be used to style the syntactic    elements of the code, and the script contains the logic to    actually assign these classes to the right pieces of text.</p>    <p>You'll usually want to use some kind of prefix for your CSS    classes, so that they are unlikely to clash with other classes,    both those used by other modes and those defined by the page in    which CodeMirror is embedded.</p>    <p id="defineMode">The mode script should    call <code>CodeMirror.defineMode</code> to register itself with    CodeMirror. This function takes two arguments. The first should be    the name of the mode, for which you should use a lowercase string,    preferably one that is also the name of the files that define the    mode (i.e. <code>"xml"</code> is defined <code>xml.js</code>). The    second argument should be a function that, given a CodeMirror    configuration object (the thing passed to    the <code>CodeMirror</code> function) and a mode configuration    object (as in the <a href="#option_mode"><code>mode</code></a>    option), returns a mode object.</p>    <p>Typically, you should use this second argument    to <code>defineMode</code> as your module scope function (modes    should not leak anything into the global scope!), i.e. write your    whole mode inside this function.</p>    <p>The main responsibility of a mode script is <em>parsing</em>    the content of the editor. Depending on the language and the    amount of functionality desired, this can be done in really easy    or extremely complicated ways. Some parsers can be stateless,    meaning that they look at one element (<em>token</em>) of the code    at a time, with no memory of what came before. Most, however, will    need to remember something. This is done by using a <em>state    object</em>, which is an object that can be mutated every time a    new token is read.</p>    <p id="startState">Modes that use a state must define    a <code>startState</code> method on their mode object. This is a    function of no arguments that produces a state object to be used    at the start of a document.</p>    <p id="token">The most important part of a mode object is    its <code>token(stream, state)</code> method. All modes must    define this method. It should read one token from the stream it is    given as an argument, optionally update its state, and return a    style string, or <code>null</code> for tokens that do not have to    be styled. For your styles, you can either use the 'standard' ones    defined in the themes (without the <code>cm-</code> prefix), or    define your own (as the <a href="../mode/diff/index.html">diff</a>    mode does) and have people include a custom theme for your    mode.<p>    <p id="StringStream">The stream object encapsulates a line of code    (tokens may never span lines) and our current position in that    line. It has the following API:</p>    <dl>      <dt><code>eol() → boolean</code></dt>      <dd>Returns true only if the stream is at the end of the      line.</dd>      <dt><code>sol() → boolean</code></dt>      <dd>Returns true only if the stream is at the start of the      line.</dd>      <dt><code>peek() → character</code></dt>      <dd>Returns the next character in the stream without advancing      it. Will return <code>undefined</code> at the end of the      line.</dd>      <dt><code>next() → character</code></dt>      <dd>Returns the next character in the stream and advances it.      Also returns <code>undefined</code> when no more characters are      available.</dd>      <dt><code>eat(match) → character</code></dt>      <dd><code>match</code> can be a character, a regular expression,      or a function that takes a character and returns a boolean. If      the next character in the stream 'matches' the given argument,      it is consumed and returned. Otherwise, <code>undefined</code>      is returned.</dd>      <dt><code>eatWhile(match) → boolean</code></dt>      <dd>Repeatedly calls <code>eat</code> with the given argument,      until it fails. Returns true if any characters were eaten.</dd>      <dt><code>eatSpace() → boolean</code></dt>      <dd>Shortcut for <code>eatWhile</code> when matching      white-space.</dd>      <dt><code>skipToEnd()</code></dt>      <dd>Moves the position to the end of the line.</dd>      <dt><code>skipTo(ch) → boolean</code></dt>      <dd>Skips to the next occurrence of the given character, if      found. Returns true if the character was found.</dd>      <dt><code>match(pattern, consume, caseFold) → boolean</code></dt>      <dd>Act like a      multi-character <code>eat</code>—if <code>consume</code> is true      or not given—or a look-ahead that doesn't update the stream      position—if it is false. <code>pattern</code> can be either a      string or a regular expression starting with <code>^</code>.      When it is a string, <code>caseFold</code> can be set to true to      make the match case-insensitive. When successfully matching a      regular expression, the returned value will be the array      returned by <code>match</code>, in case you need to extract      matched groups.</dd>      <dt><code>backUp(n)</code></dt>      <dd>Backs up the stream <code>n</code> characters. Backing it up      further than the start of the current token will cause things to      break, so be careful.</dd>      <dt><code>column() → integer</code></dt>      <dd>Returns the column (taking into account tabs) at which the      current token starts. Can be used to find out whether a token      starts a new line.</dd>      <dt><code>indentation() → integer</code></dt>      <dd>Tells you how far the current line has been indented, in      spaces. Corrects for tab characters.</dd>      <dt><code>current() → string</code></dt>      <dd>Get the string between the start of the current token and      the current stream position.</dd>    </dl>    <p id="blankLine">By default, blank lines are simply skipped when    tokenizing a document. For languages that have significant blank    lines, you can define a <code>blankLine(state)</code> method on    your mode that will get called whenever a blank line is passed    over, so that it can update the parser state.</p>    <p id="copyState">Because state object are mutated, and CodeMirror    needs to keep valid versions of a state around so that it can    restart a parse at any line, copies must be made of state objects.    The default algorithm used is that a new state object is created,    which gets all the properties of the old object. Any properties    which hold arrays get a copy of these arrays (since arrays tend to    be used as mutable stacks). When this is not correct, for example    because a mode mutates non-array properties of its state object, a    mode object should define a <code>copyState</code> method,    which is given a state and should return a safe copy of that    state.</p>    <p id="compareStates">By default, CodeMirror will stop re-parsing    a document as soon as it encounters a few lines that were    highlighted the same in the old parse as in the new one. It is    possible to provide an explicit way to test whether a state is    equivalent to another one, which CodeMirror will use (instead of    the unchanged-lines heuristic) to decide when to stop    highlighting. You do this by providing    a <code>compareStates</code> method on your mode object, which    takes two state arguments and returns a boolean indicating whether    they are equivalent. See the XML mode, which uses this to provide    reliable highlighting of bad closing tags, as an example.</p>    <p id="indent">If you want your mode to provide smart indentation    (see <a href="#option_enterMode"><code>entermode</code></a>    and <a href="#option_tabMode"><code>tabMode</code></a> when they    have a value of <code>"indent"</code>), you must define    an <code>indent(state, textAfter)</code> method on your mode    object.</p>    <p>The indentation method should inspect the given state object,    and optionally the <code>textAfter</code> string, which contains    the text on the line that is being indented, and return an    integer, the amount of spaces to indent. It should usually take    the <a href="#option_indentUnit"><code>indentUnit</code></a>    option into account.</p>    <p id="electricChars">Finally, a mode may define    an <code>electricChars</code> property, which should hold a string    containing all the characters that should trigger the behaviour    described for    the <a href="#option_electricChars"><code>electricChars</code></a>    option.</p>    <p>So, to summarize, a mode <em>must</em> provide    a <code>token</code> method, and it <em>may</em>    provide <code>startState</code>, <code>copyState</code>,    and <code>indent</code> methods. For an example of a trivial mode,    see the <a href="mode/diff/diff.js">diff mode</a>, for a more    involved example, see    the <a href="mode/javascript/javascript.js">JavaScript    mode</a>.</p>    <p>Sometimes, it is useful for modes to <em>nest</em>—to have one    mode delegate work to another mode. An example of this kind of    mode is the <a href="mode/htmlmixed/htmlmixed.js">mixed-mode HTML    mode</a>. To implement such nesting, it is usually necessary to    create mode objects and copy states yourself. To create a mode    object, there are <code>CodeMirror.getMode(options,    parserConfig)</code>, where the first argument is a configuration    object as passed to the mode constructor function, and the second    argument is a mode specification as in    the <a href="#option_mode"><code>mode</code></a> option. To copy a    state object, call <code>CodeMirror.copyState(mode, state)</code>,    where <code>mode</code> is the mode that created the given    state.</p>    <p>To make indentation work properly in a nested parser, it is    advisable to give the <code>startState</code> method of modes that    are intended to be nested an optional argument that provides the    base indentation for the block of code. The JavaScript and CSS    parser do this, for example, to allow JavaScript and CSS code    inside the mixed-mode HTML mode to be properly indented.</p>    <p>Finally, it is possible to associate your mode, or a certain    configuration of your mode, with    a <a href="http://en.wikipedia.org/wiki/MIME">MIME</a> type. For    example, the JavaScript mode associates itself    with <code>text/javascript</code>, and its JSON variant    with <code>application/json</code>. To do this,    call <code>CodeMirror.defineMIME(mime, modeSpec)</code>,    where <code>modeSpec</code> can be a string or object specifying a    mode, as in the <a href="#option_mode"><code>mode</code></a>    option.</p></div><div class="rightsmall blk">    <h2>Contents</h2>    <ul>      <li><a href="#overview">Overview</a></li>      <li><a href="#usage">Basic Usage</a></li>      <li><a href="#config">Configuration</a></li>      <li><a href="#styling">Customized Styling</a></li>      <li><a href="#api">Programming API</a></li>      <li><a href="#modeapi">Writing CodeMirror Modes</a></li>    </ul></div></div><div style="height: 2em"> </div>  </body></html>
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