HTML5 Validation and iFrame frameborder property in ie8
Lately I've been involved in a major HTML5 overhaul for one of my site and my main focus has been ensuring that the pages validate properly according to this new standard. One thing which I came across that was driving me nuts is the fact that Internet Explorer 8 does not allow you to completely eliminate the border of an iFrame using pure CSS techniques. Ironically, IE7 and IE6 were fine, but IE8 was not. If you want to completely eliminate the annoying 3D border imposed on an iFrame in IE8 you need to use the property frameborder=0. While it is a very simple fix and looks fine in IE8, the frameborder property has been discontinued in HTML5.
For example, here is what was causing validation to fail:
<iframe src="http://someurl" frameborder="0" style="border:none; overflow:hidden; width:500px; height:27px;"></iframe>
document.write("<iframe src=\"http://someurl\" frameborder=\"0\" style=\"border:none; overflow:hidden; width:500px; height:27px;\"></iframe>");
I was not able to find a solution to this everywhere I looked so I hope this helps someone with my same predicament!