<script>

     var data ="{" +

             "root:[" +

             "{name:'1',value:'0'}," +

             "{name:'6101',value:'北京市'}," +

             "{name:'6102',value:'天津市'}," +

             "{name:'6103',value:'上海市'}," +

             "{name:'6104',value:'重庆市'}," +

             "{name:'6105',value:'渭南市'}," +

             "{name:'6106',value:'延安市'}," +

             "{name:'6107',value:'汉中市'}," +

             "{name:'6108',value:'榆林市'}," +

             "{name:'6109',value:'安康市'}," +

             "{name:'6110',value:'商洛市'}" +

             "]}";

      var dataObj = eval("("+data+")");//转换为json对象

      alert(dataObj.root.length);//输出root的子对象数量

      $.each(dataObj.root,function(idx,item){

          if(idx==0){

             return true;

          }

          //输出每个root子对象的名称和值

          console.log("name:"+item.name+",value:"+item.value);

      });

 </script>