reCaptcha, IE11 (compatibility mode?) and 414 errors

[Dave]

I'm having an issue with my reCaptcha implementation on a website. Recaptcha works great, and has been for the past year or so on our site. Our company recently updated all users to IE11, and for some reason also added our website domain name into the the compatibility mode settings for all users in the company. Now, in IE11 (and it seems only with compatibility mode turned on) all users are seeing a blank white recaptcha box where the image is expected to be. The recaptcha loads, but the image to solve does not. I have determined the reason for this is that Google is serving up a 414 error for the requested image URL, which is approximately 2500 characters long. For all other browsers, the image URL turns out to be a few hundred (under 1000) characters long, but this combination in IE turns out to be extra long. Therefore, our users cannot see a recaptcha image to solve (and the audio link is also extremely long).

Has anyone experienced this..? does anyone have any idea what is causing this, or any ideas at work-arounds to get this recaptcha implementation to work with these parameters...?  To make matters even stranger, I have seen recaptcha work in one directory of a domain with IE11/compatibility mode, but then not work in another.

[Dave]

Ok, to update I may have found some more details... it turned out that the different directories were not using the EXACT same code, and one was sending a header tag, and the other was not. We are sending the header X-UA-Compatible: IE=Edge on the site where reCaptcha is not working.  If I remove this header value, the reCaptcha appears to work correctly, which is why the other directory I mention was working... it was not setting the header.

Next question - WHY?  haha.

[Dave]

Still working on this issue... I can't figure out any rhyme or reason to what's going on. I can have two IDENTICAL copies of code on different URLs, and one will work, and one will not. The one that does not work is always in IE11 with the website added to the compatibility mode list either by the user, or through a corporate policy. I can sometimes get the captcha to show up by playing with the documents mode in IE11 developer tools, but unless I manually tell the page to render in IE=x (7/8/9, sometimes 10) with the X-UA-Compatbile header, I will just not see the image and get the 414 error.

[Dave]

Here is a JSBIN of two seperate images that the google javascript generates links to... these were pulled from the same browser, and same code base, where one page was loaded with the site in the compatibility list, and other page was not.

http://jsbin.com/rufocove/3

[Dave]

I apologize for lots of replies to my original post, I just keep finding more information and want to update the post. Can anyone try the following out in IE11 and let me know if they can reproduce?

I have created a very simple jsbin for you to try, let me just lay out the parameters again. Our website is listed in the compatibility view websites list, as pushed out by our group policy. It's also obviously possible someone adds our site to their own personal list. To ensure our site displays properly in all these scenarios, we are including the X-UA-Compatible meta tag in our HTML to keep the site in IE=Edge document mode. This combination appears to cripple reCaptcha as it requests an image with a URL that is too large for Google to handle.

To reproduce... http://jsbin.com/januyupe/2

1. Open the jsbin.com link here in IE11
2. Click the GEAR > Compatibility View Settings > Add (jsbin.com) > Close
3. The page will reload, and I expect that there will be a white space where the image should show

If you use developer tools, you will see that the image IS requested, but there is a 414 error thrown by Google for the url being too long. A successful URL is under a 1000 characters long, but this scenario produces a URL in the 2500+ range which is too long for Google servers to handle (likely for attack protection - maybe?)

[James Gilliland]

We found the same problem with lead us directly to this post. Very good steps to reproduce.

You can get some interesting results if you change the document mode. I'm guessing there is some feature detection in reCAPTCHA's javascript that is triggered when compatibility is set to edge but then running in IE8 mode thanks to compatibility makes the longer URL it creates broken. Thanks IE for mixing settings and making yet another wonky environment. Hopefully reCAPTCHA can fix this quickly though.

[Dave]

I just tried today to reproduce this, and it does not appear to be happening any longer... can anyone else still reproduce? Is it possible that this has been fixed by the recaptcha team?

[James Gilliland]

Well we can narrow the deployment of the fix to a 4hr period it would seem. I can't reproduce anymore.