XMLHTTPRequest returns null in response

Question

Possible Duplicate:
Getting BLOB data from XHR request

I try to get an image from my server dynamically, but the XMLHTTPRequest returns null in the response. The Google Chrome network tool tells me that he loaded the day1.jpg, but the blob variable is null...

var xhr = new XMLHttpRequest(), blob;

xhr.open("GET", "day1.jpg", true);

// Set the responseType to blob
xhr.responseType = "blob";

xhr.addEventListener("load", function () {
    if (xhr.status === 200) {
        console.log("Image retrieved");
        blob = xhr.response;
        console.log("blob: " + blob);
    }
}, false);

// Send XHR
xhr.send();

The output is:

Image retrieved
blob: null

If its returning status code 200 and actually running there shouldn't be an issue. Try putting console.log("blob: " + xhr.response) for grins. — Snuffleupagus, Mar 05 '12 at 17:54
blob = xhr.response; console.log("blob: " + blob); is exactly the same as console.log("blob: " + xhr.response) — Franziskus Karsunke, Mar 05 '12 at 19:19
*should* be exactly the same, just like the code above *should* be working. ;p — Snuffleupagus, Mar 05 '12 at 19:21

score 4 · Accepted Answer · edited Jul 24 '18 at 06:16

4

The reason is a bug on the Chrome side (also available on v18). Reported here

edited Jul 24 '18 at 06:16

Nisse Engström

4,738
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answered Mar 05 '12 at 18:29

Zuuum

1,495
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http://www.html5rocks.com/en/tutorials/file/xhr2/ <-- Here you can see the workaround. – Franziskus Karsunke Mar 05 '12 at 20:00

score 1 · Answer 2 · answered Mar 05 '12 at 18:06

1

why use ajax to load the image (as far as I know you can't http://www.mail-archive.com/discuss@jquery.com/msg00377.html)? You can just dynamically generate an image element and set the src attribute to the image on your server.

var i = new Image();
i.onload = function()
{
   //do the stuff you need to do once it loads here
}
i.src = "day1.jpg";

answered Mar 05 '12 at 18:06

scrappedcola

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It is possible with HTML5. And I want to load a pdf file in the end. – Franziskus Karsunke Mar 05 '12 at 19:14

score 0 · Answer 3 · answered Mar 05 '12 at 17:50

0

Use the console to inspect the xhr object and see if it's being populated at all

answered Mar 05 '12 at 17:50

Andrew Hall

3,058
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If the handler is called and Google Chrome tells me it is loaded, why shouldn't it be populated? – Franziskus Karsunke Mar 05 '12 at 17:53
Try it and see what is populated in the object then. – Andrew Hall Mar 05 '12 at 17:56
2

The response is null, the status 200, the readyState 4 and everything is null. But I already told that in my question... – Franziskus Karsunke Mar 05 '12 at 19:24

score -1 · Answer 4 · answered Mar 05 '12 at 18:00

-1

I doubt that you can load images from the server dynamically, instead what you can do is update the image source dynamically and tell from whci location shoul the image be fetched/loaded

answered Mar 05 '12 at 18:00

Abhidev

7,063
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Why wouldn't he be able to? All it does it call a simple GET request (exactly like a browser would do if you typed in the URL) and returns the response (the image). – Snuffleupagus Mar 05 '12 at 18:03
and how is he supposed to use the returned data??? – Abhidev Mar 06 '12 at 05:57

XMLHTTPRequest returns null in response

4 Answers4