What is jQuery?

jQuery is a JavaScript library. That means that it's a collection of reusable JavaScript code that accomplishes common tasks — web developers often find themselves solving the same problems over and over again. Instead of engineering a solution from scratch each time, it makes sense to collect up all those useful bits into a single package that can be included and used in any project. The creators of jQuery have written code to smoothly and easily handle the most common and most tedious tasks we want to accomplish with JavaScript — and they've ironed out all the little differences that need to be worked out to get the code working in different browsers.

It's important to remember that jQuery is JavaScript, not a language of its own. It has all the same rules and is written the same way as JavaScript. Don't let that frighten you away — jQuery really does make writing JavaScript much easier.