方法一
引入<script src = "https://cdn.polyfill.io/v2/polyfill.min.js"></script>
或 <script type="text/javascript" src ="https://cdn.polyfill.io/v2/polyfill.min.js?features=es6"></script>
方法二
引入<script src="https://cdn.bootcss.com/bluebird/3.4.6/bluebird.core.js"></script>
如果IE中出现 无法加载toBlob方法 的问题
请加入以下代码:
if (!HTMLCanvasElement.prototype.toBlob) {
Object.defineProperty(HTMLCanvasElement.prototype, 'toBlob', {
value: function (callback, type, quality) {
var canvas = this;
setTimeout(function () {
var binStr = atob(canvas.toDataURL(type, quality).split(',')[1]);
var len = binStr.length, arr = new Uint8Array(len);
for (var i = 0; i < len; i++) {
arr[i] = binStr.charCodeAt(i);
}
callback(new Blob([arr], { type: type || 'image/png' }));
});
}
});
}
(完毕)