Y Combinator alum Crocodoc is launching an HTML5-based version of its online document-viewing service today.

The software reads in any kind of document and renders it in HTML5, the latest version of the HTML standard universally used in websites, in real time. Web developers can insert an HTML tag for each document uploaded to Crocodoc’s servers into their site’s code, much as they might embed a YouTube video on a page. Users can then scroll through the documents as soon as they are rendered, without needing software like Microsoft Word or Adobe Acrobat to read a particular format.

Other services like Scribd and Docstoc already offer embeddable document viewers aimed at sharing documents online. Crocodoc is more focused on the problem of large email attachments, which simultaneously take up space on mail servers and frustrate users who might not have the right version of software to open a given file.

The quality is pretty good — it’s hard to tell much of a difference between the original document and a reconstructed version on the site. Crocodoc’s HTML5-based version of one document can be seen on the left in the image above, with the original document on the right. One chief advantage of using HTML5 is that users can interact with the Crocodoc documents like they would any other document — meaning they can pull out images and copy and paste text if they want.

“We’re trying to do for Adobe Acrobat what Gmail did to Outlook,” said Ryan Damico, Crocodoc’s chief executive. “We just want to extract the 20 percent of functionality from an offline application that people actually care about and use and cut off all the extra fat.”

Crocodoc also has a number of collaboration features for its document viewing service. Multiple people can view the same document and add notes for each other on the side. Collaborators can also draw on the document and make notes on it, and then save the new marked-up version as a PDF. Aside from collaboration, there are a number of other uses. A Crocodoc users wouldn’t have to print out a contract and re-scan it once it’s signed — they’d just sign it in the document instead.

Crocodoc also supports PowerPoint slide decks and images. The company is a bit behind Scribd, which says it has published more than a billion pages online in HTML5 form and has around 60 million readers monthly. Scribd launched in 2007, whereas Crocodoc is just more than a year old.

But Crocodoc has a jump in the enterprise market by getting in the pool with enterprise social network Yammer, another red-hot startup in the collaboration and enterprise space. The company is launching its HTML5 service alongside a widget for Yammer. That means Yammer users can view any kind of supported document — whether it’s a Microsoft Word document or a PDF — and add notes from within the social network.

“It’s not really rocket science,” Damico said. “We just wanted to make something that just works.”

Crocodoc is a graduate of the winter winter 2010 class of Y Combinator, a prolific Silicon Valley incubator known for its tight network of investors and alumni companies.