This demo will show that mod_security will block the POST request if it contains certain phrases. In this case the following "forbidden" phrase will cause the request to be blocked: <script type="text/javascript"> Obviously this causes many problems. I'm unable to edit many templates using the vBulletin template manager because it contains that phrase. Furthermore, the same happens in many of my articles whenever I'm talking about something JavaScript related. Please disable the POST scanning so that POST requests don't get blocked. See http://www.modsecurity.org/documentation/modsecurity-apache/1.9.3/modsecurity-manual.html#N10176 for more information. If you want to test it yourself, just leave this message in tact, and click the "Submit Form" button below.