Javascript XHR发送多部分/表单数据 [英] Javascript XHR send multipart/form-data

问题描述

我正在尝试发送多部分/表单数据内容类型请求:

I'm trying to send a multipart/form-data content-type request:

var xhr = new XMLHttpRequest();

xhr.onreadystatechange = function(){
    if(xhr.readyState==4){
         alert(xhr.responseText);
    }
}

xhr.open("POST", url, true);
xhr.setRequestHeader("Content-Type","multipart/form-data; boundary=---------------------------275932272513031");

xhr.send('-----------------------------275932272513031 Content-Disposition: form-data; name="name"

test

----------------------------275932272513031--');

然后在php中，我只打印$_POST数组

Then in php I just print the $_POST array

print_r($_POST);

但是我每次都会得到一个空数组.我希望看到

But I get an empty array each time. I expect to see

Array (
    name => "test"
)

我在做什么错了?

推荐答案

您的代码失败，因为您使用"Enter"代替了转义的换行符(\n).
JavaScript不支持"first line[Enter]second line".如果需要带换行符的字符串，请使用"first line\nsecond line".

Your code failed because you've used "Enter" instead of an escaped line break character (\n).
JavaScript doesn't support "first line[Enter]second line". If you need a string with a line break, use "first line\nsecond line".

解决此问题后，您的代码应该可以按预期工作(需要注意的是，请注意最后的注释):

Once you've fixed this problem, your code should work as intended (with one caveat, see final note):

var xhr = new XMLHttpRequest();
xhr.onload = function() {
     alert(xhr.responseText);
};
xhr.open("POST", url, true);
xhr.setRequestHeader("Content-Type","multipart/form-data; boundary=---------------------------275932272513031");
xhr.send('-----------------------------275932272513031\n' +
         'Content-Disposition: form-data; name="name"\n\n' +
         'test\n\n' +
         '----------------------------275932272513031--');

注意:您的代码仅适用于包含UTF-8字符(不能二进制数据)的有效负载.如果您想了解有关通过XMLHttpRequest提交带有二进制数据的表单的更多信息，请参见

NOTE: Your code will only work for payloads that consists of UTF-8 characters, not binary data. If you want to learn more about submitting forms with binary data via XMLHttpRequest, see this answer and its linked references.

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