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;
}