Using them can make code semantics more intuitive and more convenient for SEO optimization. However, this new HTML5 tag cannot be recognized on IE6/IE7/IE8 and needs to be processed by JavaScript.
If it is IE9 and below, the IE browser will create HTML5 tags.
<!--[if lt IE9]>
<script type="text/javascript">
(function(){if(!/*@cc_on!@*/0)return;var e ="abbr,article,aside,audio,canvas,datalist,details,dialog,eventsource,figure,footer,header,hgroup,mark,menu,meter,nav,output,progress,section,time,video".split(','),i=e.length;while(i--){document.createElement(e[i])}})();
</script>
<![endif]-->
Add CSS styles
article,aside,dialog,footer,header,section,footer,nav,figure,menu{display:block}
In this way, IE9 and below can use h5 tags.