从JavaScript回调函数检索值 [英] Retrieving value from javascript callback function

问题描述

var display_welcome = function(){
    var fb_login_button = jQuery('#fb_login_button');
    var fb_welcome = jQuery('#fb_welcome');
    var name = '';

    FB.api('/me',function(response){
        console.log(response);
        name = response.first_name;
    });

    fb_login_button.css('display', 'none');
    fb_welcome.html('<span>Welcome, ' + name + '</span>');
    fb_welcome.css('display', 'block');
};

当用户从网站登录Facebook时调用此函数。目标是以用户的名字向用户显示欢迎消息。问题是变量'name'是FB.api（）的回调方法范围内的局部变量。

This function is called when a user logs into Facebook from a website. The goal is to display a welcome message to the user with the user's first name. The problem is the variable 'name' is a local variable inside the scope of the callback method of FB.api(). What is the best way to extract this value and use it in my function 'display_welcome'?

推荐答案

如何移动这些行代码到API的回调中？像这样：

How about moving those lines of code into the callback of the API? Like so:

var display_welcome = function（）{
var fb_login_button = jQuery（'＃fb_login_button'）;
var fb_welcome = jQuery（'＃fb_welcome'）;
var name ='';

var display_welcome = function(){ var fb_login_button = jQuery('#fb_login_button'); var fb_welcome = jQuery('#fb_welcome'); var name = '';

FB.api('/me',function(response){
    console.log(response);
    name = response.first_name;

    fb_login_button.hide();
    fb_welcome.html('<span>Welcome, ' + name + '</span>');
    fb_welcome.show();
});

};

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