When prompted for a Captcha by SU, There's no visible captcha text and no input box. The only thing visible is the "I'm a human" button.

Windows XP, FireFox 4

Form Source:

        <form method="post" action="/captcha?s=47e22f3a-3f5c-4c8c-8df9-c9b24b7b19e5">                
            <div><script type="text/javascript">
        var RecaptchaOptions = {
            theme : 'clean',
            tabindex : 0

</script><script type="text/javascript" src="http://api.recaptcha.net/challenge?k=6LcDNwYAAAAAAG_X1rC8kTtLBP6XS2Ym1N0n9kSY">

        <iframe src="http://api.recaptcha.net/noscript?k=6LcDNwYAAAAAAG_X1rC8kTtLBP6XS2Ym1N0n9kSY" width="500" height="300" frameborder="0">


        </br><textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea><input name="recaptcha_response_field" value="manual_challenge" type="hidden" />
            <script type="text/javascript">
                $(function() { $("#recaptcha_response_field").focus(); });
                You must enter the confirmation code in the box above after solving the challenge

            <input id="btn-captcha" style="font-weight: bold;" type="submit" name="post" value="&nbsp;I'm a Human Being&nbsp;" /><br>

2 Answers 2


Specific problem and fix found:

HTTPS-Everywhere forces the use of the secure reCAPTCHA API. The problem with this is the invalid certificate used; specifically, it is expired as of 09-05-04 13:32:04 (GMT).

This can be worked around by navigating to https://api-secure.recaptcha.net/ and adding a permanent exception for the certificate.

Tested on Firefox 4 final on Ubuntu 10.10 to https://superuser.com/captcha.


I can't reproduce this. In Firefox 4


Shows up just fine for me .. can you try in Firefox safe mode, or check to see if a firewall or proxy is interfering with recaptcha showing?

enter image description here

  • Hi Jeff, I'll try it now and get back to you.
    – Basic
    Commented Apr 28, 2011 at 22:27
  • Confirmed: In safe mode, captcha shows fine. I'm disabling add-ons one by one to see what triggers it. Will be back to you shortly. This is odd as I use SO frequently and never have issues with this...
    – Basic
    Commented Apr 28, 2011 at 22:36
  • Further to the above, the issue seems to be cause by HTTPS Everywhere. This also occurs on SO (and I assume other SE sites). I've had the addon installed for a considerable length of time (months) and haven't had issues before - not sure if it's recently been updated or if something about recaptcha has changed - In any case, my issue is diagnosed and I'll do without the addon for now. (I can accept your answer if you'd like this closed?)
    – Basic
    Commented Apr 28, 2011 at 22:41
  • Specifically, it's Google APIs that causes the problem.
    – Hello71
    Commented Apr 29, 2011 at 0:17

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