The goal behind the specification is to provide a minimal set of markup to "turn any website into a paged experience," Lie said. It provides rule-sets to address formatting issues such as setting the number of columns per page, how to paginate a site and how to hyphenate text.
Using a tablet, Lie demonstrated how a Web page could be viewed with a browser that supported this markup. He presented a mockup of a newspaper, complete with multiple columns and full-page ads. The experience of moving through the paper closely resembled that of using the Amazon Kindle reader for tablets, or a stand-alone magazine app such as that from "The New Yorker."
The reader could flip to the next page by swiping a finger across the screen from right to left, and jump to the index by swiping up. Nowhere in the demo did a scroll bar appear. On the desktop, a user could navigate with a mouse, or with the arrow keys and the page-up or page-down keys, or with a pop-up navigator.
"Authors should be able to [create pages] without having to hire expensive app developers, and do it in languages they know and in code they recognize," Lie said. "It doesn't take much code to do this."
An obvious market for the technology would be that of book and periodical publishers, who could redesign their websites to look like their printed editions, Lie said. They could even use CSS as the common code-base for all the editions of their products. Beyond the publishing industry, the stylesheet extension could also help Web application developers build apps that more closely resemble native desktop and mobile applications. .
"We're putting this out as a 'lab build' to let people play with it," Lie said.
At present, no browser supports this CSS markup, even Opera's own. But Lie hopes browser makers see the value in this markup, as a way to promote greater use of the Web in general. Much as CSS provided the basis for Web developers to design pages with a certain degree of elegance, GCPM would provide the basis for formatting pages in a more stylish manner.
"We're Web fundamentalists," he said, referring to Opera. "We feel all the information that mankind produces should be on the Web. And once it's there, we should have a good way of presenting it."
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