For a long time, Microsoft’s Internet Explorer was the undisputed winner of the browser wars because it was the default choice on Windows computers, and many people didn’t bother to think twice about it. Now Google, Apple, and Mozilla are providing real competition–which sounds good on the surface. Users will supposedly benefit from faster, more secure, more full-featured tools for browsing the Web. But this competition also means that each browser maker is offering a distinct vision of what a browser ought to be, and the result could be chaos for a while.

Each browser maker wants to teach users to evaluate browsers in terms that will favor its product.

Google, for example, is encouraging users to pay attention to the speed of the browser. Alex Russell, a Google software engineer who works on the Chrome browser, said on a panel at the Web 2.0 Expo in New York City this week that his company has optimized the engine that process the JavaScript typically used for Web applications. This lets the apps run much faster. Google’s overall vision is that the browser is a fast pathway onto the Internet that disappears into the background as people engage with complex Web applications as if they were using desktop software. “The manifest destiny of the browser is to give the developer access to everything the computer can do, while keeping the user safe,” Russell says.

Mozilla, which makes the Firefox browser, doesn’t want to play Google’s speed game.

Brendan Eich, Mozilla’s chief technical officer, says the browser should be the user’s representative on the Web. Firefox has given users ways to customize their Web experience - with add-ons that block ads, for instance - and now Eich says the browser can help people manage their online identity. For example, many people log into websites through social sites such as Facebook. Eich says such data instead could be stored securely in the browser and passed out to sites as needed.

Yet another vision of the browser comes from Opera Software. Hakon Wium Lie, CTO of Opera, stresses the idea that people should have the same experience on the Web no matter what device they’re using. Indeed, Opera has focused much effort on its Opera Mini browser, which is the most popular browser on mobile phones.

The problem with having these differing visions is that it can make it harder for Web developers to design their sites. If developers choose to support advanced features offered by only one browser, they are potentially cutting out a large portion of the audience for a website. Or if they aim to serve the largest possible number of users, they might have to skip new features such as those enabled by the new HTML5 Web standard. HTML5 will add significant animation and video capabilities to the browser. This also means Web users will find sites that look different depending on which browser they have. Google has been releasing experiments that showcase the capabilities of Chrome and don’t really work properly in other browsers.

“In the short term, life will get much worse for Web developers,” says Douglas Crockford, an architect at Yahoo who is an expert on JavaScript.