时间戳转为日期格式

easyui datagrid 日期时间显示不正常，后台java 类型为时间戳 经过JSON工具一转化传到前台来就是这样，不便 于是想格式化一下，

$('#gridTable').datagrid({

         title:'系统通知及广告管理',

         loadMsg:'数据加载中,请稍后……',

         rownumbers:true,

         pagination:true,

         singleSelect:false,

         pageSize: 10,

         pageList: [5, 10, 15, 20],

         fitColumns:true,

   fit:true,

         striped:true,

         nowrap:false,

         url:'list.do',

         idField:'mediaId',

   columns:[[

    {field:'id',checkbox:true},

    {field:'system',title:'适用系统'},

    {field:'infoType',title:'消息类型',

     formatter:

             function(value, row, index){

             if(value==1)

              return"文本";

             if(value==2)

              return"图片";

             if(value==3)

              return"视频";

             else

              return"<span style=\"color:red\" >未知</span>";

      }},

           {field:'title',title:'标题'},

           {field:'content',title:'内容',width:140},

       {field:'issueTime',title:'生效时间',

            formatter:function(value,row,index){

             varunixTimestamp = newDate(value);

             returnunixTimestamp.toLocaleString();

             }

     },

       {field:'disabledTime',title:'失效时间'},

       {field:'userId',title:'用户ID'},

       {field:'userName',title:'操作员'}

   ]],