localStorage 保存对象Object

localStorage 只能保存字符串，如果直接setItem 一个对象，则会执行Object 的toString() 方法，保存其结果

    var testObj = {        "userName": "xixi",        toString: function () {            return "userName:'xixi'";        }    };    localStorage.setItem("myobject", testObj);     alert(localStorage.getItem("myobject"));