blocks|key|3629318|text|因为只有在ajax调用完成之后，联系人的值才会雪崩。因此，您需要通过一个回调函数来完成这个任务，这个回调函数处理ajax结果。喜欢|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3629319|function+DBManager()+{

++++this.getContactsList+=+function(cb)+{
++++++++$.post('/post/getContactsList',+function+(contacts)+{
++++++++++++cb(contacts);
++++++++});
++++}
}

FF_DBManager.getContactsList(function(data){

++++console.log(data);

});|code-block|syntax|javascript|3629320|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Because the value of contacts avalable only after the ajax call is completed. So you need to do it by a callback function which processes the ajax result. like

<pre><code>function DBManager() {

 this.getContactsList = function(cb) {
 $.post('/post/getContactsList', function (contacts) {
 cb(contacts);
 });
 }
}

FF_DBManager.getContactsList(function(data){

 console.log(data);

});
</code></pre>

blocks|key|3086538|text|当您进行函数调用时，该函数依次发出ajax请求，这基本上是一个异步请求。此时，返回将是undefined，但一旦ajax调用完成，它将返回正确的值。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3086539|function+DBManager()+{

++++this.getContactsList+=+function()+{
++++++++$.post('/post/getContactsList',+function+(contacts)+{
++++++++++++console.log(contacts);
++++++++++++return+contacts;
++++++++});
++++}
}

var+FF_DBManager+=+new+DBManager();

console.log(FF_DBManager.getContactsList());|code-block|syntax|javascript|3086540|您可以尝试在回调方法中添加一个console.log(contacts);，以查看基本上返回了什么。|3086541|否则，如果您真的想使用ajax并等待返回，那么您可以尝试使ajax调用同步而不是异步。|3086542|$.ajax的一个简单示例|3086543|$.ajax({
++type:+'POST',
++url:+url,
++data:+data,
++success:+success,
++dataType:+dataType,
++async:false
});|3086544|entityMap^0|17|9|0|0|F|M|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|11|8|@]|D|@]|E|$]]|$1|O|3|P|5|6|7|12|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|S|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|T|$]]

When you make the function call, the function in turn makes the ajax request which is basically an async request. At this time the return will be <code>undefined</code> but once the ajax call gets completed, it will return the correct value.

<pre><code>function DBManager() {

 this.getContactsList = function() {
 $.post('/post/getContactsList', function (contacts) {
 console.log(contacts);
 return contacts;
 });
 }
}

var FF_DBManager = new DBManager();

console.log(FF_DBManager.getContactsList());
</code></pre>

You can try adding a <code>console.log(contacts);</code> in the callback method to see what is basically returned.

Else if you really want to make use of ajax and wait for the return then you can try for making ajax call synchronous instead of asynchronous

A simple example for $.ajax

<pre><code>$.ajax({
 type: 'POST',
 url: url,
 data: data,
 success: success,
 dataType: dataType,
 async:false
});
</code></pre>

blocks|key|3629394|text|我喜欢在这些情况下使用一个例子。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3629395|同步函数是这样工作的。你告诉你妻子你要出去买东西，给她一张空白的纸，让她把她要你买的东西写下来。你等她把它写下来，然后去商店。|3629396|异步函数是这样工作的。你告诉你的妻子你要出去购物，给她一张空白的纸，让她写下她想让你买的东西，等她买完后，把纸给你，让你去商店；你会等待她的指示。然后你忘记它，开始读你的晚报。|3629397|使用异步函数而不了解您所做的事情，就像您在最初的文章中所做的那样，您做了类似的事情。你告诉你的妻子你要出去购物，给她一张空白的纸，让她写下她想让你买的东西，等她买完后，把报纸给你，让你去商店。然后你立即去商店，当你找不到你妻子的文件时，你会感到困惑。你回家，继续读晚报。然后你的妻子给了你她的清单，并试图告诉你去商店，但你忽略了她，认为你的工作已经完成。|3629398|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|L|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|M|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

An example I like to use in these situations.

Synchronous functions work like this. You tell your wife you're going out and you'll do some shopping, hand her a blank piece of paper and tell her to write down the stuff she wants you to buy. You wait till she writes it down, then go to the store.

Asynchronous functions work like this. You tell your wife you're going out and you'll do some shopping, hand her a blank piece of paper, tell her to write down the stuff she wants you to buy, and when she's done, to give you the paper and tell you to go to the store; you'll be awaiting her instructions. Then you forget about it and start reading your evening paper.

Using asynchronous functions without understanding what you do, like you did in the original post, you did something like this. You tell your wife you're going out and you'll do some shopping, hand her a blank piece of paper, tell her to write down the stuff she wants you to buy, and when she's done, to give you the paper and tell you to go to the store. You then immediately go to the store, and get confused when you can't find your wife's paper on you. You go home, and proceed to read the evening paper. Your wife then gives you her list and tries to tell you to go to the store, but you ignore her, thinking your job is done.

My code looks like:

<pre><code>function DBManager() {

 this.getContactsList = function() {
 $.post('/post/getContactsList', function (contacts) {
 return contacts;
 });
 }
}

var DBManager = new DBManager();

console.log(FF_DBManager.getContactsList());
</code></pre>

But I get <code>undefined</code> instead of seeing the results from the post's response.

AJAX and returns (async related)

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我的代码看起来是：function DBManager() {    this.getContactsList = function() {        $.post('/post/getContactsList', function (contacts) {            return contacts; ...

问AJAX与返回(异步相关)
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问AJAX与返回(异步相关)EN