Apple's Safari browser now passes the Acid2 browser test, joining a select group of browsers that offer full standards support. Will other browsers follow its lead?Macintosh users who downloaded the free Mac OS X 10.4.3 update not only received a handful of security fixes, but also a version of Apple Computer Inc.'s default Safari Mac Web browser that supports the Acid2 browser test.
Version 2.0.2 of Safari is now one of few browsers that support Acid2.
The Acid2 test was concocted by the grassroots Web Standards Project (WaSP) to promote World Wide Web Consortium Web-based content standards.
The test is a complex test Web page that features a simple graphic of a smiley face with the text "Hello World!" However, the page is constructed from elements that test the viewing browser's ability to handle HTML4, CSS1, PNG and Data URL features according to W3C standards. If the browser does not meet all of these standards, the image will not be presented properly. For example, if the browser does not implement hovering effects properly, the image's nose will not turn red when a user hovers the cursor over it.
"It's not just for browsers," said Molly Holzschlag, a Web designer and group lead for WaSP, "but anything that renders HTML, ZHTML, CSS and so on, such as a design view in a software program such as [Macromedia's] Dreamweaver."
"Acid2 is particularly important because of the current state of browser incompatibilities, which is making life very difficult for developers and designers," she said.
"At this point in history," she added, "having the specs supported is necessary for us to do our jobs more efficiently, offer real savings to our clients, improve speed, address document management issues, create more beautiful yet maintainable designs, address accessibility concerns, multiple platform and device delivery and search optimization."
George Staikos, a developer working on the K Desktop Environment (KDE) and its Konqueror Web browser, agreed that "Acid2 is important because, as a small isolated example, it illustrates strict standards compliance and error handling ability in a Web rendering engine."
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"These standards are designed to avoid repetition of the problems of the browser wars," he said. "At that time there was quite some fragmentation in the HTML supported by various user agents, and quirks in browsers were even used as competition vectors. This led to a large-scale mess of Web sites that were either incompatible with a subset of the browsers out there, or had special cases all over to handle each browser.
"With strong standards support," he added, "Web developers will be able to develop for a specification instead of a subset of popular implementations. Acid2 has helped to raise awareness of this issue and is reigniting the drive for standards support in modern Web browsers."
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Thomas Ford, a representative for Opera Software ASA, developer of the Opera Web browser, said, "Acid2 is an extremely important test because it shows that the browser can support the Web standards that govern presentation and user interaction. These standards will supply the foundation for future Web pages and help spur new innovation on the Web."
"We are excited Safari has passed Acid2," he said. "As more browsers pass [the Opera 9 TP had one minor bug, so we are closing in], there will be greater interoperability between Web technologies. For developers, this will help them design, test and publish pages much faster and with greater ease. It will also help free the Web of proprietary technologies that hinder advancement."
Next Page: Will other browsers catch up?
Apple is not the only developer pursuing the compatibility goal set by the Acid2 test. As mentioned above, Opera Software has reached within one bug of Acid2 compliance with its Opera 9 Technology Preview, though the company cannot say when the final version of Opera 9 will be available.
"Konqueror as of Version 3.5 passes the Acid2 test as well," said Staikos. "I can't get any confirmation right now," he added, "but I think 3.4.3 also comes close to passing, if it doesn't pass completely. Konqueror 3.5 will be released later this month."
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Holzschlag added that "Konqueror and iCab respectively pass at the code level."
Safari is based on the WebKit application framework that debuted in Mac OS X 10.3. WebKit, which Apple open-sourced in mid-2005, includes two lower-level frameworks—JavaScriptCore and WebCore—an HTML parser and renderer based on KHTML.
"As soon as Safari passed in WebKit," Holzschlag said, "those
browsers were next up, with iCab apparently coming in a tad bit before Konqueror."
Holzschlag noted that another WaSP member, Dean Edwards, maintains a Web page handicapping browsers and their Acid2 compatibility.
"Safari was in a good position to push forward as fast as they did." Holzschlag said.
In comparison, she said, "Microsoft is at a disadvantage because they want not only to comply with the specifications but also have to manage compatibility within their proprietary platform."
"Mozilla Firefox is headed in that direction," she added, "but both Mozilla and Microsoft have stated that they feel Acid2 compliance isn't necessarily a benchmark as there are limitations to the test itself. However, the pressure is certainly on, and I have little doubt that Mozilla and Microsoft developers are keeping an eye on Acid2 compliance, even if it's not their first priority in terms of browser fixes."
Holzschlag mentioned that she recently met with Internet Explorer Product Manager Chris Wilson. She said that Wilson described his three main issues for Microsoft's Web browser: "User experience [interface features such as tabbed browsing], security and platform. The platform is where the standards work is going on—everything in there is about specifications, fixing HTML and XHTML support, fixing CSS support," Holzschlag said.
"All of these things are being addressed by Microsoft," she said.
In addition, she said, "Microsoft Visual Studio and the ASP.Net platform are also constantly improving standards support. The new generation of design tools from Microsoft support XHTML and CSS out of the box. I've seen it myself, and it's looking very, very good."
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She stressed that "smaller tool makers have perhaps been the quickest to compliance. BBEdit for the Mac is an excellent, standards-compliant editor. Homesite is also quite good. StyleMaster from WestCiv has always held standards as a core feature."
Holzschlag said that there is still much to do. She singled out assistive devices such as screen readers, Web-enabled cell phones and PDAs as well as content management systems as especially needing work in building in standards compliance.
Next Page: The challenges of standards support.
So, why don't more browsers support all the relevant Web standards by default?
"As far as developing for Acid2, it is a challenge," said Opera's Ford.
"But the real trick is coding for Acid2 while making sure the browser doesn't break any existing pages," he said. "That is the trick."
"Someone could code a browser that passes Acid2, but then is useless with the rest of the Web. It seems that Safari has done a good job with this part," he said.
And, for most developers and users, it's more critical that a browser renders existing pages rather than supports standards, said KDE's Staikos.
"There are few or no cases where browsers not supporting the latest standards prevents it from rendering a page," he said.
Most Web sites, he said, "are developed for the browser and not for the standards." For example, there are still Web sites using Internet Explorer-only extensions of relying on specific browser bugs in order to display pages.
"This is changing, though," Staikos said. "Web developers want to have standards and develop for them, and all the browsers are improving their support for standards."
"In most cases I think it's economically tempting, in the short term, to just support the 90 percent [of users who use a particular browser], worry about the 8 percent later and worry about the 2 percent after that," he said. He noted that testing for multiple browsers on multiple platforms can be seen by managers as not worth the investment.
"However," he said, "as the market becomes more diverse, I think we'll find that the pressure to implement standards will sharply increase.
"This could be accelerated by mobile and embedded devices where browsers have more restrictions in what they can do, and are sometimes complete rewrites or based on other engines which are standards compliant," he added.
When asked what sanction browser developers could face if they produced non-compliant browsers, Staikos said, "Nothing except customer request, political pressure and peer pressure."
Apple representatives could not be reached for comment.
Editor's Note: This story was updated to correct an assertion that the iCab browser was based on the KHTML engine. iCab is not based on the KHTML engine, but it does pass the Acid2 test.
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