AJAX not working under Apache2?

Question

PHP

AJAX does not work under Apache2. Status code: 0, status: failed. I can't figure out what the problem is. On other sites on the same server, everything works as it should. The request is not cross-domain, of the form
url: '/ajax/do/delete'
Here is the site config:

<VirtualHost *:80>
        ServerName site.com
        DocumentRoot /var/www/site.com
        <Directory /var/www/site.com/>
                Options Indexes FollowSymLinks
                AllowOverride All
                Order allow,deny
                allow from all
        </Directory>

        ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
        <Directory "/usr/lib/cgi-bin">
                AllowOverride None
                Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
                Order allow,deny
                Allow from all
        </Directory>

        ErrorLog ${APACHE_LOG_DIR}/error.log

        # Possible values include: debug, info, notice, warn, error, crit,
        # alert, emerg.
        LogLevel warn

        CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

Answer 1

Found a reason. Sorry for my inattention. AdBlock just blocked all my requests. After turning it off, everything worked. Thank you all for your response.

Answer 2

AJAX is a normal request, the main difference is only in the headers sent to the server ($_SERVER["HTTP_X_REQUESTED_WITH"]).
Get Firefox+Firebug (Network tab) or another tool and browser. Send a request and see what comes up there. Most likely you have an error in the code, and some kind of exception is thrown along with the response.