<canvas> 兼容IE8 ， 文本（txt）无法在IE中显示出来

ctx.fillText(txt,x+3, y+15);

加上这两个方法 文本（txt）还是无法在IE中显示出来，求助sos,谢谢

contextPrototype.measureText = function(textToDraw) {

var hiddenSpan = document.createElement('span');

hiddenSpan.style.font = this.font;

hiddenSpan.innerHTML = textToDraw;

var bodyNode = document.getElementsByTagName("body")[0];

bodyNode.appendChild(hiddenSpan);

var width = hiddenSpan.offsetWidth;

bodyNode.removeChild(hiddenSpan);

this.strokeStyle = '#000';

this.fillStyle = '#000';

this.font = '12px sans-serif';

return {"width" : width + 1};

}

contextPrototype.fillText=function(textToDraw, x, y) {

var vmlStr = [];

var textHeightStr = this.font.split("px")[0].replace(/(^\s+)|(\s+$)/g, "");

var textHeight = /^\d+$/.test(textHeightStr) ? parseInt(textHeightStr) : 0;

vmlStr.push(' ' >' + textToDraw,

' ',

'');

this.element_.insertAdjacentHTML('BeforeEnd', vmlStr.join(''));   

};

我也是这样，你搞定了么，怎么弄的