CODEWITHSUNDEEP
javascriptxmlhttprequestresponsefilesize
valeryan
valeryan

Reputation: 354

Why length of XMLHttpRequest response differs from size of requested file?

If actual size of file is 6327 bytes (and content-length in response header is 6327),

then why length of XMLHttpRequest response (value of xhr.response.length in code below) is different:

6085 in Chrome (Version 41) and 5961 in Firefox (Version 36)?

//run this code somewhere on google.com to avoid access error
var xhr = new XMLHttpRequest();
xhr.open('GET','https://www.google.com/images/errors/robot.png',true);
xhr.onreadystatechange=function(e){
    if(xhr.readyState==4&&xhr.status==200){
        console.log(xhr.response.length);
    }
};
xhr.send();

Command

xhr.setRequestHeader('Content-Type','image/png');

or command

xhr.setRequestHeader('Content-Type','application/zip');

does not help.

Upvotes: 4

Views: 7414

Answers (1)

valeryan
valeryan

Reputation: 354

MIME type must be overridden:

var xhr = new XMLHttpRequest();
xhr.open('GET','https://www.google.com/images/errors/robot.png',true);
xhr.overrideMimeType('text/plain; charset=x-user-defined');
xhr.onreadystatechange=function(e){
    if(xhr.readyState==4&&xhr.status==200){
        console.log(xhr.response.length);
    }
};
xhr.send();

Actually, it not the best answer to question, but works correctly (value of xhr.response.length is equal to file size).

Upvotes: 4

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