JS 获取json长度

var keleyijson={"plug1":"myslider","plug2":"zonemenu","plug3":"keleyi"}

    function JSONLength(obj) {

        var size = 0;

        var key;

        for (key in obj) {   //obj中存在几个关键字

            if (obj.hasOwnProperty(key))

            size++;

        }

        return size;

    };

document.write("json对象的元素个数是："+JSONLength(keleyijson));