Facebook Login button stopped rendering

I have a test page where I am trying to work out the problems of the Facebook Login button. I tried somethin开发者_运维问答g, put things back to how they were, and now the button stopped rendering.

The page is here: http://www.comehike.com/test_fb_connect.php

Any idea why the button doesn't show up?

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First, clear your browser's cache and cookies. A commenter stated that the button renders for him/her, so it could be a local issue.

Second ensure that your Facebook developer account is active.

Third, use Firebug to check the requests between your site and Facebook. This may reveal any obvious errors.