jQuery Introduction

jQuery is a small JavaScript library that makes working with web pages easier. Its motto is write less, do more: one short line can find elements, change them and react to clicks. It was the most used JavaScript library for years, and it is still on a huge number of websites, so you will meet it in real code.

To use jQuery, add its script to the page (from a CDN, a link to a hosted copy). Then everything starts with the $ function: $(selector) finds elements, and methods change them.

$(document).ready(...) waits until the page is loaded. In the example the heading text changed and both notes turned teal. A shorter form is $(function () { ... }).