JS+canvasでGIFアニメーションを動作させます

if('getContext'indocument.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() { varcanvas = document.createElement('canvas'); // 尺寸 varwidth =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; } } }; } varimage = 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'; } }; }