Rich-Text Editing in Mozilla

Introduction

Mozilla 1.3 introduces an implementation of Microsoft^® Internet Explorer's designMode feature. The rich-text editing support in Mozilla 1.3 supports the designMode feature which turns HTML documents into rich-text editors. Starting in Firefox 3, Mozilla also supports Internet Explorer's contentEditable attribute which allows any element to become editable or non-editable (the latter for when preventing change to fixed elements in an editable environment).

Setting Up Rich-Text Editing

Rich-text editing is initialized by setting the designMode property of a document to "On", such as the document inside an iframe. Once designMode has been set to "On", the document becomes a rich-text editing area and the user can type into it as if it were a textarea. The most basic keyboard commands such as copy and paste are available, all others need to be implemented by the website.

Similarly, setting contentEditable to "true" allows you to make individual elements of a document editable.

Executing Commands

When an HTML document has been switched to designMode, the document object exposes the document.execCommand method which allows one to run commands to manipulate the contents of the editable region. Most commands affect the document's selection (bold, italics, etc), while others insert new elements (adding a link) or affect an entire line (indenting). When using contentEditable, calling execCommand will affect the currently active editable element.

Internet Explorer Differences

One major difference between Mozilla and Internet Explorer that affects designMode is the generated code in the editable document: while Internet Explorer uses HTML tags (em, i, etc), Mozilla 1.3 will generate by default spans with inline style rules. The styleWithCSS command can be used to toggle between CSS and HTML markup creation.

Figure 1 : Generated HTML differences

Mozilla:

<span style="font-weight: bold;">I love geckos.</span>
<span style="font-weight: bold; font-style: italic; 
    text-decoration: underline;">Dinosaurs are big.</span>

Internet Explorer:

<STRONG>I love geckos.</STRONG>
<STRONG><EM><U>Dinosaurs are big.</U></EM></STRONG>

Another difference between Mozilla and IE is how to access the document object of an iframe, which is usually used in conjunction with designMode. Mozilla uses the W3C standard way, namely IFrameElement.contentDocument, while IE requires IFrameElement.document.

DevEdge provides a JavaScript helper class, xbDesignMode, which is a wrapper for the designMode feature which hides the differences between IE and Mozilla.

Event Handling Disabled

A further difference for Mozilla is that once a document is switched to designMode, all events on that particular document are disabled. Once designMode is turned off however (as this now seems possible in Mozilla 1.5) the events become active again.

More information can be found in the Rich text editing section of Migrate apps from Internet Explorer to Mozilla.

Examples

Please note: The example files are still being migrated from another site. They are not available at this time. --fumble 18:13, 24 Apr 2005 (PDT)

Example 1

The first example is an HTML document setting its own designMode to "On". This makes the entire document editable in Mozilla 1.3. Internet Explorer, however, does not allow javascript to change the current document's designMode. For it to work in Internet Explorer, the contentEditable attribute of the body tag needs to be set to "true".

Figure 2 : First example

HTML:
<body contentEditable="true" onload="load()">

JavaScript:
function load(){
  window.document.designMode = "On";
}

Example 2

The second example is a simple rich text editing page, where text can be bolded/italicized/underlined, new links can be added and the color of text changed. The example page consists of an iframe, which will be the rich editing area, as well as elements for basic editing commands such as bold/italics/text color.

Figure 3 : Setting up rich-text editing

HTML:
<body onload="load()">

JavaScript:
function load(){
  getIFrameDocument("editorWindow").designMode = "On";
}

function getIFrameDocument(aID){
  // if contentDocument exists, W3C compliant (Mozilla)
  if (document.getElementById(aID).contentDocument){
    return document.getElementById(aID).contentDocument;
  } else {
    // IE
    return document.frames[aID].document;
  }
}

The example contains a doRichEditCommand function that makes it easier to execute commands on the iframe's document and keeps the HTML code clean. The function executed the requested command using execCommand() and then sets focus back to the editable document, as clicking on a button will set focus on the button itself, which breaks the editing flow.

Figure 4 : Executing Rich Editing Commands

HTML:
<button onclick="doRichEditCommand('bold')" style="font-weight:bold;">B</button>

JavaScript:
function doRichEditCommand(aName, aArg){
  getIFrameDocument('editorWindow').execCommand(aName,false, aArg);
  document.getElementById('editorWindow').contentWindow.focus()
}

Example: a simple but complete Rich Text Editor

<!doctype html>
<html>
<head>
<title>Rich Text Editor</title>
<script type="text/javascript">
var oDoc, sDefTxt;

function initDoc() {
  oDoc = document.getElementById("textBox");
  sDefTxt = oDoc.innerHTML;
  if (document.compForm.switchMode.checked) { setDocMode(true); }
}

function formatDoc(sCmd, sValue) {
  if (validateMode()) { document.execCommand(sCmd, false, sValue); oDoc.focus(); }
}

function validateMode() {
  if (!document.compForm.switchMode.checked) { return true ; }
  alert("Uncheck \"Show HTML\".");
  oDoc.focus();
  return false;
}

function setDocMode(bToSource) {
  var oContent;
  if (bToSource) {
    oContent = document.createTextNode(oDoc.innerHTML);
    oDoc.innerHTML = "";
    var oPre = document.createElement("pre");
    oDoc.contentEditable = false;
    oPre.id = "sourceText";
    oPre.contentEditable = true;
    oPre.appendChild(oContent);
    oDoc.appendChild(oPre);
  } else {
    if (document.all) {
      oDoc.innerHTML = oDoc.innerText;
    } else {
      oContent = document.createRange();
      oContent.selectNodeContents(oDoc.firstChild);
      oDoc.innerHTML = oContent.toString();
    }
    oDoc.contentEditable = true;
  }
  oDoc.focus();
}

function printDoc() {
  if (!validateMode()) { return; }
  var oPrntWin = window.open("","_blank","width=450,height=470,left=400,top=100,menubar=yes,toolbar=no,location=no,scrollbars=yes");
  oPrntWin.document.open();
  oPrntWin.document.write("<!doctype html><html><head><title>Print<\/title><\/head><body onload=\"print();\">" + oDoc.innerHTML + "<\/body><\/html>");
  oPrntWin.document.close();
}
</script>
<style type="text/css">
.intLink { cursor: pointer; }
img.intLink { border: 0; }
#toolBar1 select { font-size:10px; }
#textBox {
  width: 540px;
  height: 200px;
  border: 1px #000000 solid;
  padding: 12px;
  overflow: scroll;
}
#textBox #sourceText {
  padding: 0;
  margin: 0;
  min-width: 498px;
  min-height: 200px;
}
#editMode label { cursor: pointer; }
</style>
</head>
<body onload="initDoc();">
<form name="compForm" method="post" action="sample.php" onsubmit="if(validateMode()){this.myDoc.value=oDoc.innerHTML;return true;}return false;">
<input type="hidden" name="myDoc">
<div id="toolBar1">
<select onchange="formatDoc('formatblock',this[this.selectedIndex].value);this.selectedIndex=0;">
<option selected>- formatting -</option>
<option value="h1">Title 1 &lt;h1&gt;</option>
<option value="h2">Title 2 &lt;h2&gt;</option>
<option value="h3">Title 3 &lt;h3&gt;</option>
<option value="h4">Title 4 &lt;h4&gt;</option>
<option value="h5">Title 5 &lt;h5&gt;</option>
<option value="h6">Subtitle &lt;h6&gt;</option>
<option value="p">Paragraph &lt;p&gt;</option>
<option value="pre">Preformatted &lt;pre&gt;</option>
</select>
<select onchange="formatDoc('fontname',this[this.selectedIndex].value);this.selectedIndex=0;">
<option class="heading" selected>- font -</option>
<option>Arial</option>
<option>Arial Black</option>
<option>Courier New</option>
<option>Times New Roman</option>
</select>
<select onchange="formatDoc('fontsize',this[this.selectedIndex].value);this.selectedIndex=0;">
<option class="heading" selected>- size -</option>
<option value="1">Very small</option>
<option value="2">A bit small</option>
<option value="3">Normal</option>
<option value="4">Medium-large</option>
<option value="5">Big</option>
<option value="6">Very big</option>
<option value="7">Maximum</option>
</select>
<select onchange="formatDoc('forecolor',this[this.selectedIndex].value);this.selectedIndex=0;">
<option class="heading" selected>- color -</option>
<option value="red">Red</option>
<option value="blue">Blue</option>
<option value="green">Green</option>
<option value="black">Black</option>
</select>
<select onchange="formatDoc('backcolor',this[this.selectedIndex].value);this.selectedIndex=0;">
<option class="heading" selected>- background -</option>
<option value="red">Red</option>
<option value="green">Green</option>
<option value="black">Black</option>
</select>
</div>
<div id="toolBar2">
<img class="intLink" title="Clean" onclick="if(validateMode()&&confirm('Are you sure?')){oDoc.innerHTML=sDefTxt};" src="data:image/gif;base64,R0lGODlhFgAWAIQbAD04KTRLYzFRjlldZl9vj1dusY14WYODhpWIbbSVFY6O7IOXw5qbms+wUbCztca0ccS4kdDQjdTLtMrL1O3YitHa7OPcsd/f4PfvrvDv8Pv5xv///////////////////yH5BAEKAB8ALAAAAAAWABYAAAV84CeOZGmeaKqubMteyzK547QoBcFWTm/jgsHq4rhMLoxFIehQQSAWR+Z4IAyaJ0kEgtFoLIzLwRE4oCQWrxoTOTAIhMCZ0tVgMBQKZHAYyFEWEV14eQ8IflhnEHmFDQkAiSkQCI2PDC4QBg+OAJc0ewadNCOgo6anqKkoIQA7" />
<img class="intLink" title="Print" onclick="printDoc();" src="data:image/png;base64,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">
<img class="intLink" title="Undo" onclick="formatDoc('undo');" src="data:image/gif;base64,R0lGODlhFgAWAOMKADljwliE33mOrpGjuYKl8aezxqPD+7/I19DV3NHa7P///////////////////////yH5BAEKAA8ALAAAAAAWABYAAARR8MlJq7046807TkaYeJJBnES4EeUJvIGapWYAC0CsocQ7SDlWJkAkCA6ToMYWIARGQF3mRQVIEjkkSVLIbSfEwhdRIH4fh/DZMICe3/C4nBQBADs=" />
<img class="intLink" title="Redo" onclick="formatDoc('redo');" src="data:image/gif;base64,R0lGODlhFgAWAMIHAB1ChDljwl9vj1iE34Kl8aPD+7/I1////yH5BAEKAAcALAAAAAAWABYAAANKeLrc/jDKSesyphi7SiEgsVXZEATDICqBVJjpqWZt9NaEDNbQK1wCQsxlYnxMAImhyDoFAElJasRRvAZVRqqQXUy7Cgx4TC6bswkAOw==" />
<img class="intLink" title="Remove formatting" onclick="formatDoc('removeFormat')" src="data:image/png;base64,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">
<img class="intLink" title="Bold" onclick="formatDoc('bold');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAInhI+pa+H9mJy0LhdgtrxzDG5WGFVk6aXqyk6Y9kXvKKNuLbb6zgMFADs=" />
<img class="intLink" title="Italic" onclick="formatDoc('italic');" src="data:image/gif;base64,R0lGODlhFgAWAKEDAAAAAF9vj5WIbf///yH5BAEAAAMALAAAAAAWABYAAAIjnI+py+0Po5x0gXvruEKHrF2BB1YiCWgbMFIYpsbyTNd2UwAAOw==" />
<img class="intLink" title="Underline" onclick="formatDoc('underline');" src="data:image/gif;base64,R0lGODlhFgAWAKECAAAAAF9vj////////yH5BAEAAAIALAAAAAAWABYAAAIrlI+py+0Po5zUgAsEzvEeL4Ea15EiJJ5PSqJmuwKBEKgxVuXWtun+DwxCCgA7" />
<img class="intLink" title="Left align" onclick="formatDoc('justifyleft');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAIghI+py+0Po5y02ouz3jL4D4JMGELkGYxo+qzl4nKyXAAAOw==" />
<img class="intLink" title="Center align" onclick="formatDoc('justifycenter');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAIfhI+py+0Po5y02ouz3jL4D4JOGI7kaZ5Bqn4sycVbAQA7" />
<img class="intLink" title="Right align" onclick="formatDoc('justifyright');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAIghI+py+0Po5y02ouz3jL4D4JQGDLkGYxouqzl43JyVgAAOw==" />
<img class="intLink" title="Numbered list" onclick="formatDoc('insertorderedlist');" src="data:image/gif;base64,R0lGODlhFgAWAMIGAAAAADljwliE35GjuaezxtHa7P///////yH5BAEAAAcALAAAAAAWABYAAAM2eLrc/jDKSespwjoRFvggCBUBoTFBeq6QIAysQnRHaEOzyaZ07Lu9lUBnC0UGQU1K52s6n5oEADs=" />
<img class="intLink" title="Dotted list" onclick="formatDoc('insertunorderedlist');" src="data:image/gif;base64,R0lGODlhFgAWAMIGAAAAAB1ChF9vj1iE33mOrqezxv///////yH5BAEAAAcALAAAAAAWABYAAAMyeLrc/jDKSesppNhGRlBAKIZRERBbqm6YtnbfMY7lud64UwiuKnigGQliQuWOyKQykgAAOw==" />
<img class="intLink" title="Quote" onclick="formatDoc('formatblock','blockquote');" src="data:image/gif;base64,R0lGODlhFgAWAIQXAC1NqjFRjkBgmT9nqUJnsk9xrFJ7u2R9qmKBt1iGzHmOrm6Sz4OXw3Odz4Cl2ZSnw6KxyqO306K63bG70bTB0rDI3bvI4P///////////////////////////////////yH5BAEKAB8ALAAAAAAWABYAAAVP4CeOZGmeaKqubEs2CekkErvEI1zZuOgYFlakECEZFi0GgTGKEBATFmJAVXweVOoKEQgABB9IQDCmrLpjETrQQlhHjINrTq/b7/i8fp8PAQA7" />
<img class="intLink" title="Add indentation" onclick="formatDoc('outdent');" src="data:image/gif;base64,R0lGODlhFgAWAMIHAAAAADljwliE35GjuaezxtDV3NHa7P///yH5BAEAAAcALAAAAAAWABYAAAM2eLrc/jDKCQG9F2i7u8agQgyK1z2EIBil+TWqEMxhMczsYVJ3e4ahk+sFnAgtxSQDqWw6n5cEADs=" />
<img class="intLink" title="Delete indentation" onclick="formatDoc('indent');" src="data:image/gif;base64,R0lGODlhFgAWAOMIAAAAADljwl9vj1iE35GjuaezxtDV3NHa7P///////////////////////////////yH5BAEAAAgALAAAAAAWABYAAAQ7EMlJq704650B/x8gemMpgugwHJNZXodKsO5oqUOgo5KhBwWESyMQsCRDHu9VOyk5TM9zSpFSr9gsJwIAOw==" />
<img class="intLink" title="Hyperlink" onclick="var sLnk=prompt('Write the URL here','http:\/\/');if(sLnk&&sLnk!=''&&sLnk!='https://'){formatDoc('createlink',sLnk)}" src="data:image/gif;base64,R0lGODlhFgAWAOMKAB1ChDRLY19vj3mOrpGjuaezxrCztb/I19Ha7Pv8/f///////////////////////yH5BAEKAA8ALAAAAAAWABYAAARY8MlJq7046827/2BYIQVhHg9pEgVGIklyDEUBy/RlE4FQF4dCj2AQXAiJQDCWQCAEBwIioEMQBgSAFhDAGghGi9XgHAhMNoSZgJkJei33UESv2+/4vD4TAQA7" />
<img class="intLink" title="Cut" onclick="formatDoc('cut');" src="data:image/gif;base64,R0lGODlhFgAWAIQSAB1ChBFNsRJTySJYwjljwkxwl19vj1dusYODhl6MnHmOrpqbmpGjuaezxrCztcDCxL/I18rL1P///////////////////////////////////////////////////////yH5BAEAAB8ALAAAAAAWABYAAAVu4CeOZGmeaKqubDs6TNnEbGNApNG0kbGMi5trwcA9GArXh+FAfBAw5UexUDAQESkRsfhJPwaH4YsEGAAJGisRGAQY7UCC9ZAXBB+74LGCRxIEHwAHdWooDgGJcwpxDisQBQRjIgkDCVlfmZqbmiEAOw==" />
<img class="intLink" title="Copy" onclick="formatDoc('copy');" src="data:image/gif;base64,R0lGODlhFgAWAIQcAB1ChBFNsTRLYyJYwjljwl9vj1iE31iGzF6MnHWX9HOdz5GjuYCl2YKl8ZOt4qezxqK63aK/9KPD+7DI3b/I17LM/MrL1MLY9NHa7OPs++bx/Pv8/f///////////////yH5BAEAAB8ALAAAAAAWABYAAAWG4CeOZGmeaKqubOum1SQ/kPVOW749BeVSus2CgrCxHptLBbOQxCSNCCaF1GUqwQbBd0JGJAyGJJiobE+LnCaDcXAaEoxhQACgNw0FQx9kP+wmaRgYFBQNeAoGihCAJQsCkJAKOhgXEw8BLQYciooHf5o7EA+kC40qBKkAAAGrpy+wsbKzIiEAOw==" />
<img class="intLink" title="Paste" onclick="formatDoc('paste');" src="data:image/gif;base64,R0lGODlhFgAWAIQUAD04KTRLY2tXQF9vj414WZWIbXmOrpqbmpGjudClFaezxsa0cb/I1+3YitHa7PrkIPHvbuPs+/fvrvv8/f///////////////////////////////////////////////yH5BAEAAB8ALAAAAAAWABYAAAWN4CeOZGmeaKqubGsusPvBSyFJjVDs6nJLB0khR4AkBCmfsCGBQAoCwjF5gwquVykSFbwZE+AwIBV0GhFog2EwIDchjwRiQo9E2Fx4XD5R+B0DDAEnBXBhBhN2DgwDAQFjJYVhCQYRfgoIDGiQJAWTCQMRiwwMfgicnVcAAAMOaK+bLAOrtLUyt7i5uiUhADs=" />
</div>
<div id="textBox" contenteditable="true"><p>Lorem ipsum</p></div>
<p id="editMode"><input type="checkbox" name="switchMode" id="switchBox" onchange="setDocMode(this.checked);" /> <label for="switchBox">Show HTML</label></p>
<p><input type="submit" value="Send" /></p>
</form>
</body>
</html>

Note: if you want to see how to standardize the creation and the insertion of your editor in your page, please see our more complete rich-text editor example.

Resources

Original Document Information

Author(s): Doron Rosenberg, Netscape Communications
Published: 04 Apr 2003
Revised: 01 Jul 2003
Revised: 24 Apr 2005, Joel Coreson
Revised: 28 Nov 2006, Ken Kuhns, ComputronicsUSA
Revised: 19 Dec 2007, Mark Finkle