JQuery Callback function

The Callback function executes after the current animation 100% is complete.

Since the JavaScript statements (instructions) are executed one at a-in order, the statements after the animation may produce errors or page conflicts, because the animation is not finished, and to avoid this, you can add the Callback function as a parameter.

When animation 100% is complete, the Callback function is called.

A typical syntax:

$ (selector). Hide (Speed,callback)

The callback parameter is a function that is executed after the hide operation is completed.

For example:

$ ("P"). Hide (1000,function () {

Alert ("P is hidden, this sentence will be alert out");

})

You need to execute the statement after a function that involves animation, using the callback function.

Callback && callback ();

Execute if there is a callback function!
This is a little trick of using JS && notation
The && symbol will not execute the following statement when it is false in the front.
So this is the equivalent of

if(callback){

　　callback();

 }

JQuery Callback function