Q:

Browser Security Error: "This page can't be displayed due to a security violation"

I work for a web development firm, and I designed a page for some of our marketing people to add custom footers to various pages in our application.  We have various test environments before we deploy our product for the world to see. 
The problem is, when someone tries to add a javascript:(void) call to the footer HTML, they are presented with a blank page with the following error message:
ERROR

error

This page can't be displayed due to a security violation.  Contact support for additional information. 

a picture is shown here:

The error will go away if the user gets rid of the Javascript:void calls.  Is this error a server error?  There is no code that directly handles this error in our application, and the browser returned a 200 OK POST response. 
This error is only occurring in our public-accessible environments, which again leads me to believe it is a server issue. 
Any help or information on this error would be great. 

A:

Looks like it was a firewall issue.  I brought it up to my network manager and he knows what to do now.  The issue was related to Imperva, which sits in front on the server, monitoring traffic and blocking "threatening" requests. 