function isEmpty(s) {
    return (s == null) || (s.length == 0);
}
function isValidEmailAddress(s) {
    var at, dot;
    if (s == null || s.length == 0) {
        return false;
    }
        
    at = s.indexOf('@');
    dot = s.lastIndexOf('.');
    if (at <= 0) {
        return false;
    }
    else if (dot <= 0 || dot < at) {
        return false;
    }
    else if (dot == (s.length - 1)) {
        return false;
    }
    return true;
}
function isFloat(s) {
    var seenDecimalPoint = false;
    var k;
    if ((s == null) || (s.length == 0)) {
        return false;
    }
    else if (s == ".") {
        return false;
    }
    for (k = 0; k < s.length; ++k) {
        var c = s.charAt(k);
        if ((c == ".") && !seenDecimalPoint) {
            seenDecimalPoint = true;
        }
        else if ((c < "0") || (c > "9")) {
            return false;
        }
    }
    return true;
}
function isInteger(s) {
    var k;
    if ((s == null) || (s.length == 0)) {
        return false;
    }
    for (k = 0; k < s.length; ++k) {
        var c = s.charAt(k);
        if ((c < "0") || (c > "9")) {
            return false;
        }
    }
    return true;
}