After lurking inconspicuously within the code of websites for more than a decade, JavaScript has emerged to become a key battleground in a second era of web-browser wars.
JavaScript, which lets developers create everything from basic website menus to online spreadsheet applications, was born in the mid-1990s when Microsoft's Internet Explorer challenged the incumbent browser, Netscape's Navigator. IE won that war, but now it faces its own challenge from the heir to the Navigator throne, Mozilla's Firefox, along with upstarts including Google's Chrome, Apple's Safari and Opera.
All the challengers tout JavaScript performance as a major part of their competitive attack — even to the point of naming their JavaScript engines built into their browsers: Chrome's V8, Firefox's TraceMonkey, Opera's Futhark and upcoming Carakan and Safari's newly branded Nitro, which is Apple's version of WebKit's Squirrelfish.
Although IE lags behind all these rivals in JavaScript performance, Microsoft does care about performance overall and JavaScript performance specifically. The company launched a brand-new browser version, Internet Explorer 8, on Thursday. "We're going to keep making the script engines faster [but] right now it's not clear how many people are gated by script performance," IE general manager Dean Hachamovitch said in an interview. "JavaScript comprises a small portion of how fast a web page will render. It is a piece, but by no means the holy grail."
Because it is easy to measure, JavaScript performance has "become shorthand for browser performance", Hachamovitch added. Microsoft has begun touting its new test of page-loading speeds in which IE8 fared better overall than Firefox 3.0.5 and Chrome 1.0. A supporting slow-motion video (to view the video, click on Case Study Videos then Performance Testing) shows page-loading speeds down to the hundredth of a second.
Meanwhile, the day before the IE8 launch, Google launched its Chrome Experiments site to tout what can be done with high-performance JavaScript and to promote its browser. While Chrome generally runs sites' applications with aplomb, that is not the case for IE.
Browsing vs running applications
The difference between the companies seem to boil down to one difference: the fact Microsoft is focusing on today's web, and its rivals are focusing on tomorrow's.
The internet is growing from being a web made of static pages to be read with links to be clicked, into a web that also includes applications that perform computational tasks and that people interact with. In other words, browsers now have to process data as well as load pages. Microsoft's dominant share — 67 percent according to Net Applications' figures — reflects the more mainstream world, and the challengers are aiming for where they think the mainstream will be going.
"The faster we make JavaScript, the more interesting and interactive the web becomes," said Mike Beltzner, Mozilla's director of Firefox.
Google agrees. "We saw a lot of web developers lamenting the fact that they couldn't do what they wanted to do because JavaScript was a limiting factor," said Darin Fisher, a Chrome engineer at Google. It's certainly not the only bottleneck, but Google concluded that "by far the biggest performance opportunity we saw was to improve JavaScript".
Google has a direct interest in faster JavaScript. It is among the biggest advocates of cloud computing, in which internet-based applications and services replace those running natively on a personal computer.
But Google Docs, Google Calendar and Gmail are not rarities. Yahoo, Facebook and countless other sites make extensive use of JavaScript, and Microsoft itself is working to produce online versions of its Office suite.
AdventNet's Zoho division, which also offers web-based tools for word processing, spreadsheets and other tasks, is another company eager for faster JavaScript. Currently the company has to show a separate site with reduced abilities to people who use IE6 with the site, said Zoho chief executive Sridhar Vembu.
"We're excited because this represents a fundamental breakthrough in JavaScript performance and capability for applications like ours," Vembu said of the new generation of browsers. "Within a year I think we'll see such browsers dominating the landscape."
Vembu is also optimistic that Microsoft will close the JavaScript gap with its rivals. "I believe Microsoft will catch up," he said.
To emphasise only JavaScript for web applications is to oversimplify the situation. (And of course there are any number of other aspects of browser quality, including security, plug-in availability, operating-system support, user interface responsiveness and website support.) Web applications also benefit from...
