function IsNumeric(sText) {
	   var ValidChars = "0123456789";
	   var IsNumber=true;
	   var Char;

	   for (i = 0; i < sText.length && IsNumber == true; i++){
	      Char = sText.charAt(i);
	      if (ValidChars.indexOf(Char) == -1) {
	         IsNumber = false;
	      }
	   }
	   return IsNumber;
	}

	function validate_required(field,alerttxt) {
		with (field) {
			if (value==null||value=="") {
				alert(alerttxt);return false;
			} else {
				return true
			}
		}
	}

	function validate_number(field,alerttxt) {
		with (field) {
			if (!IsNumeric(value)) {
				alert(alerttxt);return false;
			} else {
				return true
			}
		}
	}

	function validate_email(field,alerttxt) {
		with (field) {
			apos=value.indexOf("@");
			dotpos=value.lastIndexOf(".");
			if (apos<1||dotpos-apos<2){alert(alerttxt);return false;}
			else {return true;}
		}
	}