History of JavaScript: Part 4

2010-06-14 00:00:00 +0100 by Alex R. Young

This article is part 4 of our History of JavaScript series. Last week we
looked at the development of Rhino, and the downfall of JavaScript 2.
This week I'm going to dig into Ajax and JavaScript frameworks


As we've already seen, Microsoft had a version of
XMLHttpRequest pretty early on. Mozilla quickly followed,
by adding support to Gecko, but it wasn't fully-functional until around
2002. Other browsers eventually implemented similar functionality, prior
to standardisation by the W3C.

Meanwhile, Jesse James Garrett published an
essay entitled Ajax: A New Approach to Web

in February 2005. Garrett cited XMLHttpRequest as a major
component in what Adaptive Path dubbed Ajax.

The importance of this new approach quickly became apparent. The main
lesson people took away from the essay was the power of asynchronous
client-side code. The term Ajax quickly became synonymous with the more
awkward term XMLHttpRequest.

I still prefer Adaptive Path's original definition of Ajax, and I think
it's useful to draw a distinction between the terms. It hasn't helped
that certain popular JavaScript libraries confuse Ajax with


The W3C published a working draft for the XMLHttpRequest
object in April 2006. The last version is draft 19, published November
2009, at

Even though the first draft of this spec was 2006, 2005 was the start of
the web 2.0 revolution.

The Rise of Web 2.0

Interest in web applications waned after the dot com crash. This was the
era in which I graduated, so I have first-hand experience trying to
survive in that period. Thankfully, by 2005 Garrett's essay and popular
sites like Google Maps inspired a new breed of web application.

I remember colleagues telling me that Ajax was dangerous because of the
number of HTTP requests clients would generate back to the server. It
was actually very rare that this was a problem, and JavaScript libraries
started to appear that addressed web 2.0 technologies like

The first library I remember using was Prototype by Sam Stephenson. It
used a lot of conventions from Ruby, and it was popular with Ruby
developers due to ties with Rails. It made XMLHttpRequest
easy to use, and it also patched a lot of cross-browser issues which had
plagued JavaScript development.

Other libraries also appeared in 2005:

Scriptaculous built on Prototype to provide rich UI features.

A New Type of API

Libraries like Prototype were influenced by other programming languages.
Their internal structures and APIs are similar to traditional OO
classes. While libraries were battling to support the next fashionable
UI widget, other developers were wondering if there was a more natural
way to work with JavaScript in the browser.

One of these brave souls was John Resig. In Selectors in
he discusses
a library called Behaviour, and ponders ways of linking JavaScript code
to CSS selectors.

By pushing what JavaScript could do natively, he had created the basis
of jQuery. A year later, jQuery 1.0 was

Historical Lessons

I have a lot of respect for Sam Stephenson, Thomas Fuchs and John Resig.
They took their projects in different directions and made a lot of
things easier for us developers in the trenches. The lesson we can take
away from this period, however, is that playing to the strengths of your
language will always pay off in the end.

As kangax pointed out this year, Prototype's approach of extending the
DOM has major issues. It looks like Prototype 2 might work more like
jQuery. Rather than bringing in a Ruby, Python or Java influence, Resig
stuck to his guns and looked at how to write natural JavaScirpt, and
this approach paid off.