使用js下载base64 图片

太懒了,直接贴vue中的代码,自己感悟

            downLoadQRcode() {
                if(!!this.imgUrl) {
                    let imgData = this.imgUrl;
                    this.downloadFile('QRcode.jpg', imgData);
                }
            },
            // 下载
            downloadFile(fileName, content) {
                let aLink = document.createElement('a');
                let blob = this.base64ToBlob(content); // new Blob([content]);
                let evt = document.createEvent('HTMLEvents');
                evt.initEvent('click', true, true);// initEvent 不加后两个参数在FF下会报错  事件类型，是否冒泡，是否阻止浏览器的默认行为
                aLink.download = fileName;
                aLink.href = URL.createObjectURL(blob);
                aLink.dispatchEvent(new MouseEvent('click', {bubbles: true, cancelable: true, view: window}));// 兼容火狐
            },
            // base64转blob
            base64ToBlob(code) {
                let parts = code.split(';base64,');
                let contentType = parts[0].split(':')[1];
                let raw = window.atob(parts[1]);
                let rawLength = raw.length;

                let uInt8Array = new Uint8Array(rawLength);

                for(let i = 0; i < rawLength; ++i) {
                    uInt8Array[i] = raw.charCodeAt(i);
                }
                return new Blob([uInt8Array], {type: contentType});
            },