使用JS和canvas实现gif动图的停止和播放实例页面

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代码:

HTML代码:
<img id="testImg" src="xxx.gif" width="224" height="126">
<p><input type="button" id="testBtn" value="停止"></p>
                
JS代码:
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';
        }
    };
}
                

效果: