HTML5 tag support for IE<9 in 222 bytes

html5ie.js

for(var a="abbr article aside audio bdi canvas data datalist details figcaption figure footer header hgroup mark meter nav output progress section summary time video".split(" "),b=a.length;b--;)document.createElement(a[b])

note

Is safer to use this code inside an IIFE (Immediately-Invoked Function Expression)

(function () { /* code */ }());