Working with Prototype

No other library, toolset, or invention has led to the explosive growth of Ajax more than Prototype, the freely available Ajax/JavaScript library created by Sam Stephenson and available at It’s become so popular, it’s integrated as part of the Ruby on Rails (RoR) development environments. Several other libraries reviewed in this chapter and in previous chapters are based on Prototype.

What Prototype offers is a way to emulate a classlike behavior based on the JavaScript prototype; it provides a set of functions that hide much of the underlying JavaScript behavior. This is good because JS can be cumbersome when you’re trying to access several elements in a page and have to get each one using something like getElementById. However, as has been noted frequently, Prototype also hides many of the underlying mechanisms, which can make reading any code that uses the library confusing—especially for newer JavaScript developers or those unfamiliar with Prototype. Luckily, this won’t include you after the following brief peek.

Download, Install, Use

One aspect of Prototype I really appreciate is that it’s one library, included in one JavaScript file, and easily integrated into a page. Just include a link to the downloaded Prototype library in your application:

<script type="text/javascript" src="prototype.js">

That’s it (assuming you put the prototype.js file on your server). You’re now ready to use Prototype functions ...

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