How can I create an Asynchronous function in Javascript?

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.

You can use a timer:

setTimeout( yourFn, 0 );

(where yourFn is a reference to your function)

or, with Lodash:

_.defer( yourFn );

Defers invoking the func until the current call stack has cleared. Any additional arguments are provided to func when it's invoked.