Function Declaration And Function Expression in jQuery

Sometimes developer’s get confused between these two topics (I am saying about the starters like me). Basically both function declaration and function expression are same. Only difference depends on how you handle or treat these two. We will see a basic demo here to ensure the difference between function declaration and expression. I hope you will like this.

Here I am using jQuery 2.0.2 version, you can use whichever version you like.

Background

In my project I am using both function declarations and function expressions. So I thought to highlight some basic difference between them, so it may help someone.

The basic difference between function declaration and function definition:

• Function declarations are loaded first, that is before any codes.
• Function expressions are loaded when the interpreter reaches that particular line of code.
• Basically we can call any code only after the declarations are loaded.

We will try to find out this difference with a demo.

Using the code

First thing you need to do is create a page.

Then you need to include the script needed.

Now we will create a function declaration as follows.

What will be the output of this?


Function Declaration And Function Expression.

Now we will change our script as follows.

This will also return the same output.


Now we will create a function expression as follows.