When updating our website from XHTML to HTML5, will changing the following things result in rendering problems for our site in older browsers like Internet Explorer 8:

  1. Specify <!doctype html>. (The current XHTML web pages are well-formed enough)

  2. Add new specific HTML5 semantic block tags like <header> and <article>. We are not going to use CSS for these tags - just wrap the existing parts of the site.

  3. Add microdata attributes to the existing tags like <p>.

After reading some books and many Internet articles, I see no problems as the new tags and attributes will be simply excluded from rendering as unknown in those older browsers. However, I admit, in practice there can be some issues, especially with IE. Does anybody have any real experience with that?


1 Answer 1


Doctype and Microdata shouldn't create many problems. It's possible that it will throw IE into 'quirks' mode, but you will probably be fine.

The problem with HTML5 tags like header and article are that older browsers don't recognize them as block level elements. So if you are using them in that way at all you may be in for some layout surprises.

There are polyfills, like html5shiv - https://code.google.com/p/html5shiv/, that will handle those problems if you want to use it.

  • 1
    I would just add to test your pages with target browsers if it's a concern prior to production. You can use VM images, or a screenshot service like this one just for visualizing layouts.
    – dan
    Feb 4, 2014 at 1:30
  • I thought such unrecognized tags as <header> would be simply skipped, so they should not affect the layout at all. I'm not going to apply any CSS styles to them. Do I need Modernizer or HTML5Shiv in this case too?
    – TecMan
    Feb 4, 2014 at 7:05
  • As long as you aren't using them to separate block level content, then no, you will be fine and shouldn't need anything else. Feb 4, 2014 at 20:02

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