// base64 转 blobdataURItoBlob(dataURI) { // convert base64/URLEncoded data component to raw binary data held in a string let byteString; if (dataURI.split(',')[0].indexOf('base64') >= 0) { byteString = atob(dataURI.split(',')[1]); } else byteString = unescape(dataURI.split(',')[1]); // separate out the mime component const mimeString = dataURI .split(',')[0] .split(':')[1] .split(';')[0]; // write the bytes of the string to a typed array const ia = new Uint8Array(byteString.length); for (let i = 0; i < byteString.length; i++) { ia[i] = byteString.charCodeAt(i); } return new Blob([ia], { type: mimeString });},