Question

51

Javascript XHR send multipart/form-data

rated 0 times [ 53] [ 2] / answers: 1 / hits: 19455 / 11 Years ago, sun, december 22, 2013, 12:00:00

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--');

Then in php I just print the $_POST array

print_r($_POST);

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

Array (

    name => test

)

What am I doing wrong?

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ulysses

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4 Years ago

answered 11 Years ago kinsley · Accepted Answer

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 linensecond line.

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('-----------------------------275932272513031n' +

         'Content-Disposition: form-data; name=namenn' +

         'testnn' +

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

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.