function Validate_Required(sender, args) {
    if (args.Value == "") {
        args.IsValid = false;
        ShowValidation(sender, false);
        return;
    }

    ShowValidation(sender, true);
    args.IsValid = true;
}

function Validate_Email(sender, args) {
    if ((args.Value == "") || (IsEmail(args.Value) == false)) {
        args.IsValid = false;
        ShowValidation(sender, false);
        return;
    }

    ShowValidation(sender, true);
    args.IsValid = true;
}

function ShowValidation(sender, isValid) {
    //var id = sender.previousElementSibling.id;

    control = $("#" + sender.id);
    var id = control.prev().attr("id");

    if (isValid) {
        $("#" + id).removeClass("not_valid");
    }
    else {
        $("#" + id).addClass("not_valid");
    }
}

function IsEmail(email) {
    var sQtext = '[^\\x0d\\x22\\x5c\\x80-\\xff]';
    var sDtext = '[^\\x0d\\x5b-\\x5d\\x80-\\xff]';
    var sAtom = '[^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+';
    var sQuotedPair = '\\x5c[\\x00-\\x7f]';
    var sDomainLiteral = '\\x5b(' + sDtext + '|' + sQuotedPair + ')*\\x5d';
    var sQuotedString = '\\x22(' + sQtext + '|' + sQuotedPair + ')*\\x22';
    var sDomain_ref = sAtom;
    var sSubDomain = '(' + sDomain_ref + '|' + sDomainLiteral + ')';
    var sWord = '(' + sAtom + '|' + sQuotedString + ')';
    var sDomain = sSubDomain + '(\\x2e' + sSubDomain + ')*';
    var sLocalPart = sWord + '(\\x2e' + sWord + ')*';
    var sAddrSpec = sLocalPart + '\\x40' + sDomain; // complete RFC822 email address spec
    var sValidEmail = '^' + sAddrSpec + '$'; // as whole string

    var reValidEmail = new RegExp(sValidEmail);

    if (reValidEmail.test(email)) {
        return true;
    }

    return false;
}