You need some client script to achieve this. Here is a simple sample:

<SCRIPT ID=clientEventHandlersJS LANGUAGE=javascript>
<!--

var IsChanged;

IsChanged=0;

function test_onchange() {

IsChanged=1

}

function window_onbeforeunload() {
if (IsChanged)
alert("changed!");
}

//-->
</SCRIPT>
</HEAD>
<BODY LANGUAGE=javascript onbeforeunload="return window_onbeforeunload()">

<P>


<INPUT id="test" LANGUAGE=javascript onchange="return test_onchange()"
value=test>


</P>

</BODY>
</HTML>

The Textbox or DDL has an event "OnChange", we may set a flag in it and
check the flag on exit of the window.

Hope this answer your question.

Luke

"Microsoft Security Announcement: Have you installed the patch for
Microsoft Security Bulletin MS03-026?? If not Microsoft strongly advises
you to review the information at the following link regarding Microsoft
Security Bulletin MS03-026
[url]http://www.microsoft.com/security/security_bulletins/ms03-026.asp[/url] and/or to
visit Windows Update at [url]http://windowsupdate.microsoft.com[/url] to install the
patch. Running the SCAN program from the Windows Update site will help to
insure you are current with all security patches, not just MS03-026."