Learning PHP, MySQL & JavaScript, 5th Edition

Chapter 21. Introduction to jQuery

Powerful and flexible as JavaScript is, with its plethora of built-in functions, you still need additional layers of code for simple things that cannot be achieved natively or with CSS, such as animations, event handling, and asynchronous communication.

What’s more, as a consequence of the various browser wars over the years, frustrating and annoying browser incompatibilities have come and gone, rearing their heads at different times on different platforms and programs.

As a result, ensuring your web pages look the same on all devices can sometimes be achieved only through tedious JavaScript code that accounts for all the discrepancies across the range of browsers and versions released over recent years. In a word—nightmare.

To fill these gaps, a number of libraries of functions (many of which also provide easy hooks into the DOM) have been developed to minimize the differences between browsers and to facilitate asynchronous communication and event and animation handling. These include the likes of AngularJS, jQuery, MooTools, Prototype, script.aculo.us, and YUI (among many others).

Why jQuery?

There’s room to cover only one library in this book, however, so I have opted for the most widely used: jQuery, which is now installed on over 73 percent of all websites, according to W3Techs, and (as far as I can tell from their graphs) is more used than all its major competitors combined. Incidentally, if you ever want to see how the various libraries ...