jQuery Hello World
A "HELLO WORLD!!" is a simple program that outputs "HELLO WORLD!!" on the screen. Since it's a very simple program, it's often used to introduce a new programming to a newbie. Let's go over the "HELLO WORLD!!" program, which simply prints "HELLO WORLD!!" in a messeagebox.
Adding jQuery to Your Web Page
The above line shows how to include jQuery from a CDN, like Google.
Document Ready Event
Here $() indicates jQuery syntax and is used to define jQuery part. $(document).ready() method get called when document is loaded.
We have used jQuery selector here. $(#myButton) actually selects DOM element with that id, so $(#myButton) selects button and when we click on that button,click function will get called, then we called the alert function with message "HELLO WORLD!!" .