Need Onchange events for SharePoint:FormFields - sharepoint-2010

Question

I need to call a javascript function when a SharePoint:FormField has changed. This is to provide some client side feedback about there selection.
I need to add this on a new content type form, in my Visual Studio project. The SharePoint:FormField doesn't appear to have the Onchange event, like normal ASP controls.
I looked at ValueChanged event, but it looks like read only.
Any suggestions or help would be appreciated

Answer 1

Solution Found:
I resolved the problem thanks to Google and webborg.blogspot.com/2008/04/… and mysplist.blogspot.com/2010/03/…. I would add that the JavaScript should be inline and after following your SharePoint:FormField
<table cellpadding="0" cellspacing="0" id="onetIDListForm" style="width:100%">
<tr>
<td width="400px" valign="top" class="ms-formbody">
<SharePoint:FormField runat="server" ID="MyGender" ControlMode="New" FieldName="MyGender" />
<SharePoint:FieldDescription runat="server" ID="field_MyGender_Description" FieldName="My Gender" ControlMode="New" />
</td>
</tr>
</table>
<script type="text/javascript">
function getField(fieldID)
{
var docTags = document.all;
for (var i=0; i < docTags.length; i++) {
if (docTags[i].title == fieldID) {
return docTags[i]
}
}
}
function DisplayMessage()
{
if (getField('My Gender').value == 'Male') {
alert('Hello Manhood');
}
}
getField('My Gender').onchange = function() {DisplayMessage()};
</script>