使用JS和canvas实现gif动图的停止和播放代码

<img id="testImg" src="xxx.gif" width="224" height="126"><p><input type="button" id="testBtn" value="停止"></p>

if ('getContext' in document.createElement('canvas')) { HTMLImageElement.prototype.play = function() {  if (this.storeCanvas) {   // 移除存储的canvas   this.storeCanvas.parentElement.removeChild(this.storeCanvas);   this.storeCanvas = null;   // 透明度还原   image.style.opacity = '';  }  if (this.storeUrl) {   this.src = this.storeUrl;   } }; HTMLImageElement.prototype.stop = function() {  var canvas = document.createElement('canvas');  // 尺寸  var width = this.width, height = this.height;  if (width && height) {   // 存储之前的地址   if (!this.storeUrl) {    this.storeUrl = this.src;   }   // canvas大小   canvas.width = width;   canvas.height = height;   // 绘制图片帧（第一帧）   canvas.getContext('2d').drawImage(this, 0, 0, width, height);   // 重置当前图片   try {    this.src = canvas.toDataURL("image/gif");   } catch(e) {    // 跨域    this.removeAttribute('src');    // 载入canvas元素    canvas.style.position = 'absolute';    // 前面插入图片    this.parentElement.insertBefore(canvas, this);    // 隐藏原图    this.style.opacity = '0';    // 存储canvas    this.storeCanvas = canvas;   }  } };} var image = document.getElementById("testImg"),  button = document.getElementById("testBtn"); if (image && button) { button.onclick = function() {  if (this.value == '停止') {   image.stop();   this.value = '播放';  } else {   image.play();   this.value = '停止';  } };}