Place this in the header part of the html:
<html>
<head>
<script LANGUAGE="JavaScript">
<!--
// Confirm user wants to cancel the changes
function confirmCancel()
{
var cancelChanges=confirm("Are you sure you wish to cancel your changes?");
if (cancelChanges)
return true ;
else
return false ;
}
// -->
</script>
</head>
<body>
<form name="form1" method="post" action="">
<input TYPE="SUBMIT" name="sub_cancel" value="Cancel" onClick="return confirmCancel();">
</form>
</body>
</html>
Add the text in bold to your submit button.