这个ie8的兼容是个问题，ie8 的innerHTML有问题啊，添加两个附件吧
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>多用户留言系统-</title>
<meta name="description" content="">
<meta name="keywords" content="">
<!--[if IE]>
<script src="html5.js"></script>
<script src="excanvas.compiled.js"></script>
<![endif]-->
<link href="" rel="stylesheet">
<style>
/*html5*/
article,aside,dialog,footer,header,section,footer,nav,figure,menu,canvas{display:block}
</style>
</head>
<body>
<canvas >80%</canvas>
</body>
</html>
<script type="text/javascript">
window.onload = function(){
var can = document.getElementById('can');
var pro = can.innerHTML.substring(0,can.innerHTML.length-1);
console.log(pro);
var cxt = can.getContext('2d');
//底层
cxt.beginPath();
cxt.moveTo(100,100);
cxt.arc(100,100,100,0,Math.PI*2);
cxt.fillStyle='#ddd';
cxt.fill();
cxt.closePath();
//进度层
cxt.beginPath();
cxt.moveTo(100,100);
cxt.arc(100,100,100,0,Math.PI*2*90/100,false);
cxt.fillStyle='red';
cxt.fill();
cxt.closePath();
//顶层补色
cxt.beginPath();
cxt.moveTo(100,100);
cxt.arc(100,100,70,0,Math.PI * 2);
cxt.fillStyle="#fff";
cxt.fill();
cxt.closePath();
//文字
cxt.font = 'bold 40px Arial';
cxt.textAlign = 'center';
cxt.fillStyle='#333';
cxt.textBaseline = 'middle';
cxt.moveTo(100,100);
cxt.fillText(pro+'%',100,100);
}
</script>
html5.js
/** * * @authors Sam (645298225@qq.com) * @date 2016-03-09 15:17:42 * @version $Id$ */ /* HTML5 Shiv v3.7.0 | @afarkas @jdalton @jon_neal @rem | MIT/GPL2 Licensed */ (function(l,f){function m(){var a=e.elements;return"string"==typeof a?a.split(" "):a}function i(a){var b=n[a[o]];b||(b={},h++,a[o]=h,n[h]=b);return b}function p(a,b,c){b||(b=f);if(g)return b.createElement(a);c||(c=i(b));b=c.cache[a]?c.cache[a].cloneNode():r.test(a)?(c.cache[a]=c.createElem(a)).cloneNode():c.createElem(a);return b.canHaveChildren&&!s.test(a)?c.frag.appendChild(b):b}function t(a,b){if(!b.cache)b.cache={},b.createElem=a.createElement,b.createFrag=a.createDocumentFragment,b.frag=b.createFrag(); a.createElement=function(c){return!e.shivMethods?b.createElem(c):p(c,a,b)};a.createDocumentFragment=Function("h,f","return function(){var n=f.cloneNode(),c=n.createElement;h.shivMethods&&("+m().join().replace(/[\w\-]+/g,function(a){b.createElem(a);b.frag.createElement(a);return'c("'+a+'")'})+");return n}")(e,b.frag)}function q(a){a||(a=f);var b=i(a);if(e.shivCSS&&!j&&!b.hasCSS){var c,d=a;c=d.createElement("p");d=d.getElementsByTagName("head")[0]||d.documentElement;c.innerHTML="x<style>article,aside,dialog,figcaption,figure,footer,header,hgroup,main,nav,section{display:block}mark{background:#FF0;color:#000}template{display:none}</style>"; c=d.insertBefore(c.lastChild,d.firstChild);b.hasCSS=!!c}g||t(a,b);return a}var k=l.html5||{},s=/^<|^(?:button|map|select|textarea|object|iframe|option|optgroup)$/i,r=/^(?:a|b|code|div|fieldset|h1|h2|h3|h4|h5|h6|i|label|li|ol|p|q|span|strong|style|table|tbody|td|th|tr|ul)$/i,j,o="_html5shiv",h=0,n={},g;(function(){try{var a=f.createElement("a");a.innerHTML="<xyz></xyz>";j="hidden"in a;var b;if(!(b=1==a.childNodes.length)){f.createElement("a");var c=f.createDocumentFragment();b="undefined"==typeof c.cloneNode|| "undefined"==typeof c.createDocumentFragment||"undefined"==typeof c.createElement}g=b}catch(d){g=j=!0}})();var e={elements:k.elements||"abbr article aside audio bdi canvas data datalist details dialog figcaption figure footer header hgroup main mark meter nav output progress section summary template time video",version:"3.7.0",shivCSS:!1!==k.shivCSS,supportsUnknownElements:g,shivMethods:!1!==k.shivMethods,type:"default",shivDocument:q,createElement:p,createDocumentFragment:function(a,b){a||(a=f); if(g)return a.createDocumentFragment();for(var b=b||i(a),c=b.frag.cloneNode(),d=0,e=m(),h=e.length;d<h;d++)c.createElement(e[d]);return c}};l.html5=e;q(f)})(this,document);