How can I create an Asynchronous function in Javascript?

哈哈：）我的codepen 的代码笔记是：http://codepen.io/shinewaker/pen/eBwPxJ

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I mean, check it out this code :

<a href="#" id="link">Link</a>
<span>Moving</span>

$('#link').click(function () {
    console.log("Enter");
    $('#link').animate({  200 }, 2000, function() {
         console.log("finished");            
    });    
    console.log("Exit");    
});

as you can see in console, the "animate" function is Asynchronous, and it "fork" the flow of the event handler block code. In fact :

$('#link').click(function () {
    console.log("Enter");
    asyncFunct();
    console.log("Exit");    
});

function asyncFunct() {
    console.log("finished");
}

follow the flow of the block code!

If I wish to create my function asyncFunct() { } with this behaviour, how can I do it with javascript/jquery? I think there is a strategy without use setTimeout()

You cannot make a truly custom asynchronous function. You'll eventually have to leverage on a technology provided natively, such as:

setInterval
setTimeout
requestAnimationFrame
XMLHttpRequest
WebSocket
Worker
Some HTML5 APIs such as the File API, Web Database API
Technologies that support onload
... many others

In fact, for the animation jQuery uses setInterval.