function only_integer(event)
{
	if ( navigator.appName == 'Microsoft Internet Explorer' )
		e = event.keyCode;
	else
		e = event.which;
	//alert(e);
	//allow numbers + del + bckspc + enter + ctrl etc.
	if( !( ( e >= 48 && e <= 57 ) || ( e >= 96 && e <= 105 ) ) && !( e == 8 || e == 9 || e == 17 || e == 18 || e == 46 || e == 27 || e == 37 || e == 39 || e == 13 || e == 116 || e == 144 ) )
	{
		$("cert_no_hint").style.visibility = "visible";
		Event.stop(event);
	}
	else
		$("cert_no_hint").style.visibility = "hidden";
}