What is a callback function?

By on Jul 13, 2014 in Definitions

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Many people out here are confused by what a callback is. Perhaps the name makes it hard to understand. But in reality callbacks are very simple.

A callback function is a function that is passed as an argument of another function and it is invoked after some kind of event. The name “call back” can be attributed to the nature of the function, since once its parent function completes, the function that got passed as an argument gets called. In other words, the parent function “calls-back and executes the function passed as an argument.

As you can already imagine, callbacks are extremely useful. They allow for you to call a function within a function. Here you can see some examples:

    alert("The paragraph is now hidden");

In this example. Whenever you click a ‘button’ all ‘p’ tags will call the hide() function with parameters “slow” for the speed in which the ‘p’ tag should hide and a second parameter a function, which task is to ‘alert’.

Enmanuel Corvo
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