[英]Alter the content of a file before upload with FileReader using javascript
Is it possible to change the content of a file before beeing uploaded in javascript ? 在javascript中上传之前,是否可以更改文件的内容? I can read the content but changing it seems impossible. 我可以阅读内容,但更改它似乎是不可能的。
f = document.getElementById('input').files[0];
var reader = new FileReader();
reader.onload = function(e){
console.log(e.target)
e.target.result = "new content"
console.log(e.target);
};
reader.readAsDataURL(f);
You can't rewrite the value of a file input. 您无法重写文件输入的值。
You can take the content of the file and send it with Ajax though. 您可以获取文件的内容,然后使用Ajax发送。
reader.onload = function(e){
const data = new FormData();
const url = this.result;
const blob = convertUrlToBlob(url);
data.append("file_input", blob, "filename.ext");
const xhr = new XMLHttpRequest();
xhr.open('POST', '/example/url');
xhr.send(data);
};
I won't go into the detail of how to write a convertUrlToBlob
function, it is covered by this question . 我不会详细介绍如何编写convertUrlToBlob
函数, 该问题已对此进行了介绍 。
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