var isNS4 = (navigator.appName=="Netscape")?1:0;
function numonly(event) {
	if(!isNS4) {
		var ie = event.keyCode;
		if (ie!=127 && ie>31 && (ie<48 || ie>57)) {
			alert('Please enter only numerical characters in this field');
			event.returnValue = false;
		}
	}
	else {
		var mo = event.which;
		if (mo!=127 && mo>31 && (mo<48 || mo>57)) {
			alert('Please enter only numerical characters in this field');
			return false;
		}
	}
}