Modify contributor content using validation script

Question

Hi all,
I'd like to modify contributors content in a particular wysiwyg element using the external validation script. I've added a simple function to the default validation script included with SS 10gR4. Right now the part I don't get is - how to return the modified content back to the page?
Here's what I've got so far as a simple test, but it doesn't replace the original content.
function fnModiifyWysiwyg(oContent)
     var strTextContent = fnSSGetTextContent(oContent);
     strTextContent = "<b>this is a test</b>";
     oContent = strTextContent;
     return oContent;
}

Answer 1

I am trying to get at the HTML of contributed content to make sure it does not exceed 255 chars. I can't seem to figure out how to validate anything but the text part of the contributed content.
function fnSSGetTextContent(oContent)
     var strContent = '';
     if (typeof oContent == 'string')
          strContent = oContent;
     else if (typeof oContent.innerText == 'string')
          strContent = oContent.innerText;
     else if (typeof oContent.textContent == 'string')
          strContent = oContent.textContent;
     return strContent;
function testval(oContent) {
     var strTextContent = fnSSGetTextContent(oContent);
     if (strTextContent.length > 255) {
          alert("test");
     else {
          return true;
If I have content that, in design view, looks like
test
and in source mode looks like
test
The validation does not trigger (it should). If I put more than 255 chars in design mode, the validate fires and I get my alert.