The Saga of HTML Message Rendering in Outlook

The move is a significant change from previous versions of Outlook, which actually used two rendering engines: Internet Explorer's engine was used for reading content, while Word was used for editing content when a user was composing messages.

Outlook 2007 now uses the HTML parsing and rendering engine from Word 2007 to display HTML message bodies, and also does not use the same standards as Internet Explorer 7.

The move has not been well received by some bloggers like SitePoint's Kevin Yank, who says in a recent post that this new rendering engine is far worse than the previous one.

"With this release, Outlook drops from being one of the best clients for HTML email support to the level of Lotus Notes and Eudora, which, in the words of Campaign Monitor's David Grenier, "are serial killers making our email design lives hell."

Also, the Word 2007-powered authoring experience is always there, regardless of whether Word 2007 is actually installed, a Microsoft spokeswoman tells me, noting that the differential here is in the richness of the experience.

"Without Word 2007 installed, or with Word 2003 installed, you can't do things like SmartArt, charting and styles, but you do get a richer experience than what Outlook 2003 provided, such as the inclusion of hyperlinks and business cards," she said.

I also received a newly released Microsoft document titled "Information on the changes in Outlook using Word as the Email editor," which tries to explain further its rationale for this move.

Seems that, essentially, as improvements had been made in how Word 2007 handled HTML content, based on HTML and CSS standards and customer feedback, the Outlook and Word teams made the decision to unify the rendering and editing engine in Outlook by using Word's engine and "give users a superior editing experience by using Word," the document says.

However, while Microsoft does acknowledge that there are some HTML and CSS attributes that aren't currently supported by Word's rendering engine, it then goes on to say that "the capabilities that our customers most wanted for their HTML newsletters are supported by Outlook 2007.

But SitePoint's Yank disputes this, saying that he tested the two public beta versions of Outlook 2007 and "knew there was something screwy going on. Many of the newsletters I subscribed to had become unreadable, and SitePoint's own publications were looking decidedly unhealthy."

The solution? Use Microsoft's Outlook 2007 HTML and CSS validator tool, "to tell you which parts of your lean, mean HTML emails need to be replaced with old-fashioned HTML sludge. As a second step, you may want to consider giving your Outlook-based readers an easy way to switch to text-only email. Bring on PDF email. I'm ready," he says.

For its part, Microsoft has provided a list of those HTML and CSS standards that are - and are not - supported.

The company is also being non-committal about whether there are plans to add support for those missing standards, saying just that "the Word team is continually examining HTML and CSS support based on customer feedback."