Learning from jQuery

Chapter 1. Event Handling

In JavaScript, an event is the result of an action that can be detected by JavaScript—for example, the user clicking a button or the page load completing. Events are the heart of pretty much all web applications. Event handling, as you can probably tell by the name, is how we handle these events.

jQuery provides a suite of functions to make event handling considerably easier than in JavaScript alone. While this is nice, it can add overhead and remove control from you, the developer. For this reason, it is important to know how you can handle events without jQuery in pure JavaScript. In this chapter, I’ll be covering that as well as a few other topics that can help your jQuery knowledge, such as more about what events actually are and how they work.

Internet Explorer 8 and below does event handling completely differently than any other browser, and completely independently from any standards. If you’re writing an application that needs to support 99% of the market share and you cannot use jQuery, then you will need to write for these older browsers—even IE6 still has an over 5% market share at the time of writing. This chapter will cover event handling in Internet Explorer as well as in other browsers.

Listening for Events

Events in jQuery

The best way to explain events is probably by using an example, and the best example (as I’m assuming that you know jQuery) is to show an extract of jQuery code that works with events. The following code turns the anchor element ...