support HTML5 in IE8

<!--this code is used to support HTML5 in IE8-->

<!--[if IE]><script type="text/javascript">(function(){if(!/*@cc_on!@*/0)return;var e = "abbr,article,aside,audio,bb,canvas,datagrid,datalist,details,dialog,eventsource,figure,footer,header,hgroup,mark,menu,meter,nav,output,progress,section,time,video".split(',');for(var i=0;i<e.length;i++){document.createElement(e[i])}})()</script><![endif]-->