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;
}