base64 文件上传前端

// 将base64 的数据弄到form表单中
// 将base64 的代码转化为二进制
let bytes = window.atob(crop_base64.split(‘,‘)[1]);
let ab = new ArrayBuffer(bytes.length);
let ia = new Int8Array(ab);
for (let i = 0; i < bytes.length; ++ i) {
    ia[i] = bytes.charCodeAt(i);
}
let blob = new Blob([ia], {type: ‘image/jpeg‘});
let file_name = new Date();
blob.name = file_name + ‘.jpg‘;
blob.lastModifiedDate = file_name;
console.log(blob);
let form = document.getElementById(‘crop_form‘);
let form_data = new FormData(form);
// 将数据弄到 form 表单中
form_data.append(‘crop_file‘, blob, file_name);