变量在 ajax 后出现空白，但在 ajax 成功函数中具有值

Question

As the title says, I have an ajax function that I am using to call a function that assigns a value to a variable in js from my mysql db. On success, I can print the echoed data out and it appears in the console fine. However, calling the variable after the ajax call yields an empty variable. What is going on?

Code below:

request = $.ajax({ 
                        url: "/fans/get_url_tag", 
                        type: "post", success:function(data){url_tag = data; console.log(url_tag); //prints the correct value}, 
                        data: {'fbid': result.id} ,beforeSend: function(data){console.log(data);} 
                    });

//prints nothing
console.log(url_tag)

Answer 1

Sounds like the scope is wrong. Maybe just declare it before your $.ajax call:

var url_tag;
request = $.ajax({ 
                    url: "/fans/get_url_tag", 
                    type: "post", success:function(data){url_tag = data; console.log(url_tag);}, 
                    data: {'fbid': result.id} ,beforeSend: function(data){console.log(data);} 
                });

console.log(url_tag); //Should print the same value

Answer 2

您需要将console.log放在回调函数中。