Jquery UI 中的dialog的简单使用

html代码:

<link rel="stylesheet" href="JqueryUI/jquery-ui-1.9.2.min.css" /><script type="text/javascript" src='jquery-1.8.2.min.js'></script><script type="text/javascript" src='JqueryUI/jquery-ui-1.9.2.min.js'></script>

<div id="main">    <div id="login">        <form action="index.php" method="post">            <input type="text" name="username" class='input-big'/>            <input type='submit' name='submit' value='提交' class='loginbg'/>        </form>    </div></div><div id='dialog'></div>
JS代码:
window.onload = function(){        //登录验证    $('input[name=submit]').hover(function () {        $(this).addClass('tologin');    }, function () {        $(this).removeClass('tologin');    }).click(function () {        var uname = $('input[name=username]');        if (uname.val() == '') {            dialog(uname, '用户名不能为空');            return false;        }    });};//jQueryUI Dialogfunction dialog (obj, msg) {    $('#dialog').html(msg).dialog({        title : 'HDSHOP 提示：',        modal : true,        show : 'shake',        hide : 'explode',        buttons : [{            text : 'OK',            click : function () {                obj.focus();                $(this).dialog('close');            }        }]    });}