关于jquery 里的字符串拼接解决思路

关于jquery 里的字符串拼接
<table id="dg" class="easyui-datagrid" title="用户列表" 
data-options="
singleSelect:true,
collapsible:true,
fitColumns:true,
height:$(window).height() - 100,
nowrap: true,
url:'../panel?a=getcustomerlist&user_id=', 
method:'get'"
toolbar="#toolbar" 
pagination="true"
>




function getUser_id(){
return $.cookie('user_id');
}



小弟初学javascript,我想把下面定义的 getUser_id()的返回值拼接到 url:'../panel?a=getcustomerlist&user_id=',  User_id后面,请问代码怎么写?

------解决思路----------------------
<!DOCTYPE html>
<html>
<head>
<script src="http://www.w3school.com.cn/jquery/jquery-1.11.1.min.js">

</script>
<script>

$(document).ready(function() {
        function getUser_id() {
                //  return $.cookie('user_id');
                return "xxxxxx";
        }
        var t = $("#dg").attr("data-options").replace(/(.*)(url.*?)', (.*)/, '$1$2' + getUser_id() + '\',$3');
        $("#dg").attr("data-options", t);
        document.write($("#dg").attr("data-options"));
});
</script>
</head>
<body>
<table id="dg" class="easyui-datagrid" title="用户列表" 
            data-options="
            singleSelect:true,
            collapsible:true,
            fitColumns:true,
            height:$(window).height() - 100,
            nowrap: true,
            url:'../panel?a=getcustomerlist&user_id=', 
            method:'get'"
            toolbar="#toolbar" 
            pagination="true"
            >
</table>
</body>
</html>