<ul id="sortable1">
<li ><a href='' target=''>张三</a></li>
<li ><a href='' target=''>李四</a></li>
<li ><a href='' target=''>王五</a></li>
</ul>

var s="";
$('#sortable1 a').each(function(){
    s+=$(this).html()+',';
});
alert(s.substring(0,s.length-1));

<p class="showbtn"><a href="javascript:void(0);">显示遮罩层</a></p>
<div id="bg"></div>
<div class="box" style="display:none">
    <h2>jQuery 学习交流<a href="#" class="close">关闭</a></h2>
    <div class="list">
        <ul>
            <li>我是稀饭</li>
            <li>我是稀饭</li>
            <li>我是稀饭</li>
        </ul>
    </div>
</div>

/* box */
.box{position:absolute;width:600px;left:50%;height:auto;z-index:100;background-color:#fff;border:1px #ddd solid;padding:1px;}
.box h2{height:25px;font-size:14px;background-color:#aaa;position:relative;padding-left:10px;line-height:25px;color:#fff;}
.box h2 a{position:absolute;right:5px;font-size:12px;color:#fff;}
.box .list{padding:10px;}
.box .list li{height:24px;line-height:24px;}
.box .list li span{margin:0 5px 0 0;font-family:"宋体";font-size:12px;font-weight:400;color:#ddd;}
.showbtn {font:bold 24px '微软雅黑';}
#bg{background-color:#666;position:absolute;z-index:99;left:0;top:0;display:none;width:100%;height:100%;opacity:0.5;filter: alpha(opacity=50);-moz-opacity: 0.5;}

$(function () {
    $(".showbtn").click(function () {
        $("#bg").css({
            display: "block", height: $(document).height()
        });
        var $box = $('.box');
        $box.css({
            //设置弹出层距离左边的位置
            left: ($("body").width() - $box.width()) / 2 - 20 + "px",
            //设置弹出层距离上面的位置
            top: ($(window).height() - $box.height()) / 2 + $(window).scrollTop() + "px",
            display: "block"
        });
    });
    //点击关闭按钮的时候，遮罩层关闭
    $(".close").click(function () {
        $("#bg,.box").css("display", "none");
    });
});