jQuery实现简单登陆判断

<script src="jquery-1.9.1.js"></script>     <script type="text/javascript">

            $('#txtUserName').focus(function () {                 $('#txtUserName').val('');             })

            $('#txtPassWord').focus(function () {                 $('#txtPassWord').val('');             })

            $('#txtUserName').blur(function () {                 if ($('#txtUserName').val() =='')                 {                     $('#txtUserName').val('用户名不能为空');                     //重新获得焦点                   //  $('#txtUserName').focus();                 }             })             $('#txtPassWord').blur(function () {                 if ($('#txtPassWord').val() == '') {                     $('#txtPassWord').val('密码不能为空');                 }             })             $('#btnSubmit').click(function () {                 if ($('#txtUserName').val() == 'admin' && $('#txtPassWord').val() == '888888')                 { alert('登陆成功！'); }                 else { alert('登陆失败！'); }             })         })     </script> < /head> < body>

    用户名：<input id="txtUserName" type="text" value="请输入用户名" /><br />     密 码：<input id="txtPassWord" type="text" value="请输入密码" /><br />     <input id="btnSubmit" type="button" value="btnSubmit" /> < /body>