ie9以下的版本都不支持html5，包括神马360浏览器，遨游浏览器等，
但是现在的用户都用这些浏览器，
为了不造成样式错乱，所以必须走两条路：
1，兼容google，火狐，苹果，IE9
2，在IE9以下的版本，需要替换里面的标签
说这么多，一句代码就可以解决
新建一个js文件 名为：html5to4.js
/*! HTML5 Shiv vpre3.6 | @afarkas @jdalton @jon_neal @rem | MIT/GPL2 Licensed
Uncompressed source: https://github.com/aFarkas/html5shiv http://html5shim.googlecode.com/svn/trunk/html5.js */
(function(a,b){function h(a,b){var c=a.createElement("p"),d=a.getElementsByTagName("head")[0]||a.documentElement;return c.innerHTML="x",d.insertBefore(c.lastChild,d.firstChild)}function i(){var a=l.elements;return typeof a=="string"?a.split(" "):a}function j(a){var b={},c=a.createElement,f=a.createDocumentFragment,g=f();a.createElement=function(a){if(!l.shivMethods)return c(a);var f;return b[a]?f=b[a].cloneNode():e.test(a)?f=(b[a]=c(a)).cloneNode():f=c(a),f.canHaveChildren&&!d.test(a)?g.appendChild(f):f},a.createDocumentFragment=Function("h,f","return function(){var n=f.cloneNode(),c=n.createElement;h.shivMethods&&("+i().join().replace(/w+/g,function(a){return c(a),g.createElement(a),'c("'+a+'")'})+");return n}")(l,g)}function k(a){var b;return a.documentShived?a:(l.shivCSS&&!f&&(b=!!h(a,"article,aside,details,figcaption,figure,footer,header,hgroup,nav,section{display:block}audio{display:none}canvas,video{display:inline-block;*display:inline;*zoom:1}[hidden]{display:none}audio[controls]{display:inline-block;*display:inline;*zoom:1}mark{background:#FF0;color:#000}")),g||(b=!j(a)),b&&(a.documentShived=b),a)}var c=a.html5||{},d=/^<|^(?:button|form|map|select|textarea|object|iframe|option|optgroup)$/i,e=/^<|^(?:a|b|button|code|div|fieldset|form|h1|h2|h3|h4|h5|h6|i|iframe|img|input|label|li|link|ol|option|p|param|q|script|select|span|strong|style|table|tbody|td|textarea|tfoot|th|thead|tr|ul)$/i,f,g;(function(){var c=b.createElement("a");c.innerHTML="",f="hidden"in c,f&&typeof injectElementWithStyles=="function"&&injectElementWithStyles("#modernizr{}",function(b){b.hidden=!0,f=(a.getComputedStyle?getComputedStyle(b,null):b.currentStyle).display=="none"}),g=c.childNodes.length==1||function(){try{b.createElement("a")}catch(a){return!0}var c=b.createDocumentFragment();return typeof c.cloneNode=="undefined"||typeof c.createDocumentFragment=="undefined"||typeof c.createElement=="undefined"}()})();var l={elements:c.elements||"abbr article aside audio bdi canvas data datalist details figcaption figure footer header hgroup mark meter nav output progress section summary time video",shivCSS:c.shivCSS!==!1,shivMethods:c.shivMethods!==!1,type:"default",shivDocument:k};a.html5=l,k(b)})(this,document)
然后我们再引入这个js。
还有一个更简单的方法
在网站头部加入以下代码
<!--[if (lt IE 9)]>
<script type="text/javascript">(function(){var b=("abbr,article,aside,audio,canvas,datalist,details,dialog,eventsource,figure,footer,header,hgroup,mark,menu,meter,nav,output,progress,section,time,video").split(","),a=b.length;while(a--){document.createElement(b[a])}})();</script>
<![endif]-->
这样，在IE9 以下的浏览器中，就看不到html5标签了，自然样式就没有问题了