<form method="POST" name='form1'>
 <input type="submit" value="1" name="B1" onclick="quesid_no(1);">&nbsp;  
 <input type="submit" value="2" name="B2" onclick="quesid_no(2);">&nbsp;  
</form>
<script language=javascript>
function quesid_no(str)
{
  document.form1.action="exam.asp?id="+str;
  document.form1.submit();
}
</script>