To get at the contents of the editor from client script, you need to access the contents of the <iframe> tag in the page. The ID of the iframe is the name of the editor (e.g. richtext1) plus "_x5". RichTextBox v2.0 has got a property called EditorClientID , which will return this concatenation automatically. If you add an editor to the page called richtext1, there will be an HTML tag in the page like this:
<iframe id="richtext1_x5" ... ></iframe>
To access the contents of that iframe, add this code to the end of the HTML page:
<script>
alert('Document contents = ' + richtext1_x5.document.body.innerHTML);
</script>