Callback Function

Because in Javascript, function is first class object - that is - object can be instantiate from function. So it can be pass to other function as argument.

The callback function will be called inside another functions.
Consider about the scope of execution as I mention in SCOPE section

// Example of callback function

$("#btn_1").click(function() {

alert("Btn 1 Clicked");

});

Callback function is very useful in AJAX technique or handle user behavior with DOM element (JQuery).

Basic Principles when Implementing Callback Functions

Use named or Anonymous function as callbacks
Pass Parameters to Callback Functions
Make Sure Callback is a Function Before Executing It : by checking typeof
Be careful when use "this" object in callback function. Be sure the scope of "this" before use it.
Use the Call or Apply Function force "this" to specify scope.

Report abuse