使用jquery的blockui插件显示弹出层

$("#btnSubmit").click(function () {
    $.blockUI({
        message: $("#loginForm"),
        css: {
            width: '300px',
            height: '300px',
            left: ($(window).width() - 300) / 2 + 'px',
            top: ($(window).height() - 300) / 2 + 'px',
            border: 'none'
        }
    });
});
$("#btnLogin").click(function () {
    $.blockUI({
        message: "<h2>正在登录，请稍候……</h2>",
        css: {
            border: '1px solid black'
        }
    });
    setTimeout(function () { $.unblockUI() }, 1000);
});
$("#btnCancel").click(function () {
    $.unblockUI();
});

<div id="loginForm" style="display:none">
    <table>
        <tr>
            <td>用户名：</td>
            <td><input id="txtUserName" type="text" /></td>
        </tr>
        <tr>
            <td>密　码：</td>
            <td><input id="txtPwd" type="text" /></td>
        </tr>
        <tr>
            <td><input id="btnLogin" type="button" value="登录" /></td>
            <td><input id="btnCancel" type="button" value="取消" /></td>
        </tr>
    </table>
</div>