I came across this issue while noticing a
< header > element was being rendered in IE8 as a block element. After a quick search, I found this page which gives a quick and clean solution.
< !--[if lt IE 9] >.
I implemented their final piece of code:
< !-- Pulled from http://code.google.com/p/html5shiv/ -->
< !--[if lt IE 9]>
< script src="//html5shim.googlecode.com/svn/trunk/html5.js">
and it worked like a charm!