put this:
<script language="JavaScript1.2">
function checker()
{
return confirm("Are you sure you want to delete this whatever?");
}
</script>
in the <head> of your document...
then as one of your attributes in your <input type="submit"> tag, put this:
onclick="return checker();"
So it would end up like
<input type="submit" name="whatever" value="whatever" onclick="return checker();">