js操作json添加元素和数据的方法

function addServerUrlToJson() {
    var json_tem = [{"name":"a","value":1}];

    var arr  =
     {
         "name" : "aaa",
         "value" : "bbb"
     };
     json_tem.push(arr);
     document.write(JSON.stringify(json_tem));
} 

结果：[{"name":"a","value":1},{"name":"aaa","value":"bbb"}]

function addServerUrlToJson() {
    var url_path_down = "http://10.10.3.221/";
    var json_tem = {"name":"a","value":1};
    json_tem["url_path_down"] = url_path_down;
    document.write(JSON.stringify(json_tem));
} 

结果：{"name":"a","value":1,"url_path_down":"http://10.10.3.221/"}