JQuery运用ajax注册用户实例

//JS代码
function checkname() {
    var Msg = document.getElementById("d_username");
    var chk = CheckN();
    if (chk) {
        $.ajax({ url: 'registerOK.aspx',
            type: 'POST',
            data: { lb: "checkname", username: $("#username").val() },
            dataType: 'html',
            timeout: 1000,
            error: function() { alert('出现未知错误。'); },
            success: function(data) {
                if (data == "对不起，该用户名已被注册！") {
                    Msg.className = "d_err";
                    Msg.innerHTML = data;
                    $("#hiddencheckname").val("no");
                }
                if (data == "恭喜，该用户名可以注册！") {
                    Msg.className = "d_ok";
                    Msg.innerHTML = data;
               &