Подключение скрипта

<!--[if lt IE 9]> 
 <script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script> 
<![endif]-->

Или вставка кода в head

<!--[if lt IE 9]>
 <script>
  var e = ("article,aside,figcaption,figure,footer,header,hgroup,nav,section,time").split(',');
  for (var i = 0; i < e.length; i++) {
    document.createElement(e[i]);
  }
 </script>
<![endif]-->

 CSS

article, aside, audio, canvas, command, datalist, details, figcaption, figure, footer, header, hgroup, keygen, mark, menu, meter, nav, output, progress, rp, rt, ruby, section, source, summary, time, video, wbr {
    display: block;
}

 Скрипты должны располагаться в коде перед CSS