//**dataURL to blob**
???function dataURLtoBlob(dataurl) {
???????var arr = dataurl.split(‘,‘), mime = arr[0].match(/:(.*?);/)[1],
???????????bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
???????while (n--) {
???????????u8arr[n] = bstr.charCodeAt(n);
???????}
???????return new Blob([u8arr], { type: mime });
???}
???//**blob to dataURL**
???function blobToDataURL(blob, callback) {
???????var a = new FileReader();
???????a.onload = function (e) { callback(e.target.result); }
???????a.readAsDataURL(blob);
???}
???//test:
???//var blob = dataURLtoBlob(‘data:text/plain;base64,YWFhYWFhYQ==‘);
???//blobToDataURL(blob, function (dataurl) {
???// ???console.log(dataurl);
???//});
前端js实现 ?blob转base64位 ???和 ????base64位转blob
原文地址：https://www.cnblogs.com/zhaoyanhaoBlog/p/9349142.html