关于登录状态,后台应该另外做一个接口来决定是否登录

function isUserLogin() {

    var isLogin = false;

    $.ajax({

        type:"POST",

        url:domain+"/isuserlogin.html",

        async : false,

        success:function(data){

            if(data.success){

                if (data.data) {

                    isLogin = true;

                } else {

                    isLogin = false;

                }

            }else{

                isLogin = false;

            }

        },

        error:function(){

            isLogin = false;

        }

    });

    return isLogin;

}