显然是非感性404跨浏览器错误

Question

I am encountering an all-browser bug via the WP-FB-AutoConnect wordpress plugin. After successful login (confirmed via logs and session testing) the callback_function.submit() to the form is resulting in a 404 error. However, when I refresh the page, the file does in fact exist. It is as if there is some sort of encoding error in the action attribute of the element, however, I have tried all obvious fixes, from urlencode() to htmlentities().

Since I cannot provide an example because it is in a protected development environment, please allow me to describe how the plugin works. I have a strong feeling this has nothing to do with the particular plugin, and instead is a result of something I am simply not familiar with.

1. User clicks Facebook Login.
2. Facebook login prompt appears as expected, and user clicks 'allow'
3. Session is started. Confirmed in logs, and confirmed by visiting website to check session.
4. However, when the form is submitted via callback [document.callback_function.submit() contained in function provided to Facebook API] the resulting page is a 'Link appears to be broken [chrome]'.
5. The file exists. This is confirmed by refreshing the page that the browser is saying does not exist.

Some notes:

1. Permissions are correct. The page loads on refresh. The file exists.
2. This bug appears in Webkit and Moz, I didn't bother with IE because that's an entirely different set of headaches.
3. The link is correct and none of the characters in the URL appear to be encoded incorrectly.
4. Again, zero errors in any logs.

Please note: I am having a hard time describing this bug because it's very inconspicuous. I have never encountered anything like this in my 13 years of web development.

It is my hope that there is someone out there who has experienced something like this and has any input on the matter. I am really hoping that this is just a moment of humility for me. After hours and hours of debugging an invisible bug, and resisting coming here due to my lack of ability to describe the issue, I have no other choice. I cannot find any occurrence of this bug, either Facebook Login specific bugs, or generally within Javascript, browser issues or server-side issues through such avenues as Google or Stack Overflow.

Answer 1

Double check the script, from the error your browser sent, it seems as if there's an error in the script itself, which causes it to fail. PHP cannot parse errors if they happen before the site is done loading.