How can I create an Asynchronous function in Javascript?

Question

Check out this code :

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

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

As you can see in the console, the "animate" function is asynchronous, and it "fork"s 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 the use of setTimeout() ​

Answer 1

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.