function submitOnEnter(e, form_id) {
var ENTER_KEY = 13;
var code = "";
if (window.event) // IE
{code = e.keyCode;}
else if (e.which) // Netscape/Firefox/Opera
{code = e.which;}
if (code == ENTER_KEY) {
   document.getElementById(form_id).submit();
    return false;
}
}