EXCEL下载jquery 传值

$('#dg').datagrid({
     url:'<%=request.getContextPath()%>/customer/customerExcelList',
     toolbar:$('#toolbar'),
     rownumbers:true,
     columns :  [[{field:'id',hidden:true,title:'id'},
    {
    title : '操作',
    field : '_opt',//不对应数据库或json字段，取的名字
    formatter : function(value, rec) { //格式化函数添加一个操作列
     
     var id = rec.id;
     var downloaddate = rec.downloaddate;
     var url = rec.url;
     var str = id+'|'+downloaddate+'|'+url;
     var btn = '<a class="editcls" onclick="downloadExcel(\''+str+'\')" href="javascript:void(0)">下载EXCEL</a>';            
     return btn;
    }
   },

 function downloadExcel(str) {
   var strArray = str.split('|');
   var obj={};
   obj.id =strArray[0];
   obj.downloaddate =strArray[1];
   obj.url =strArray[2];
   var url = "<%=request.getContextPath()%>/customer/downLoad?"+$.param(obj);
   window.open(url);
  }