We have created a new website based on HTML5. With elements like <header>, <nav>, <section>, etc...
It is a pretty straightforward implementation in Tridion 2009 SP1. This means that most of the site is not dynamic, but built up by Tridion Templating. One of the benefits is that the content managers can use the preview functionality.
However, since the content managers are restricted to use IE8 we have to use something like Modernizr.js to format the HTML properly.
This is where the fun ends... Works fine on the website itself, but not in the Tridion Preview screen. It almost seems like it is not picking up the Javascript.
Any ideas, besides creating different preview HTML and CSS?
The answer was already in the question and unfortunately not an easy answer.
This issue seems to be only an issue for the older IE browsers (everything below IE9).
I ended up making a different preview CSS in combination with different HTML. All the HTML5 elements such as: <nav>, <header>, <article>, <section>, <aside>, etc... were changed into <div class="html5elementname">.
Cumbersome work, but the only way using IE8/IE7 and HTML5 for Tridion 2009 Preview.