利用jquery.validate异步印证用户名是否存在

经过上百次的试验试和搜索，终于把jquery.validate的各种功能用法了解清楚，网上关于jquery.validate的AJAX表单验证比较少，特别是对rules里面的remote提得比较简单，使得学习起来比较难，下面发布一下我个人的用法：

HTML头部引用：

<script type="text/javascript" src="../js/jquery-1.3.2.min.js"></script>
<script type="text/javascript" src="../js/jquery.validate.min.js"></script>
<script type="text/javascript" src="../js/messages_cn.js"></script>

HTML内容（部分）：

<form name="form1" id="form1" method="post" action="">
<dl>
? <dt>用户名：</dt>
? <dd><input name="txtUserName" id="txtUserName" type="text" class="input1" /></dd>
</dl>
</form>

JS代码部分：

$(function() {
//表单验证JS
??? $("#form1").validate({
??????? //出错时添加的标签
??????? errorElement: "span",
??????? rules: {
??????????? txtUserName: {
??????????????? required: true,
??????????????? minlength: 3,
??????????????? maxlength: 16,
??????????????? remote: {
??????????????????? type: "post",
??????????????????? url: "/tools/ValidateUserName.ashx",
??????????????????? data: {
??????????????????????? username: function() {
??????????????????????????? return $("#txtUserName").val();
??????????????????????? }
??????????????????? },
??????????????????? dataType: "html",
??????????????????? dataFilter: function(data, type) {
??????????????????????? if (data == "true")
??????????????????????????? return true;
??????????????????????? else
??????????????????????????? return false;
??????????????????? }
??????????????? }
??????????? }
??????? },
??????? success: function(label) {
??????????? //正确时的样式
??????????? label.text(" ").addClass("success");
??????? },
??????? messages: {
??????????? txtUserName: {
??????????????? required: "请输入用户名，3-16个字符（字母、数字、下划线），注册后不能更改",
??????????????? minlength: "用户名长度不能小于3个字符",
??????????????? maxlength: "用户名长度不能大于16个字符",
??????????????? remote: "用户名不可用"
??????????? }
??????? }

??? });
});

应注意的地方：

data: {
? ?username: function() {
? ?return $("#txtUserName").val();
}
有返回值，如果直接写“data: {username: $("#txtUserName").val();}”，这样是获取不到值的。