javascript confirm

<script language='javascript'>
function deleteConfirm()
{
 if(confirm('Are you sure to update or delete?'))
 {
  document.all.form1.submit();
 }
 else
 {
  return;
 }
}

</script>

 

 

    <form name="form1" action="confirmUpload.do" method="post">
     <input type='button' value='continue' onClick=deleteConfirm()>
 </form>