title: Handling 'A potentially dangerous Request.Form value was detected from the client' and informing user of this error
body: <p>i'm trying to handle the following issue</p>
  
  <blockquote>
    <p>'A potentially dangerous Request.Form value was detected from the
    client'</p>
  </blockquote>
  
  <p>However, I can't find a good tutorial which explains how to catch this error and handle it. Just to be clear I want to stop users from entering any sort of markup when filling out my form. Most of the articles dealing with this issue suggest turning off request validation. This is not something I want to do. I want to catch the error and playback the error to the user. Any help would be greatly appreciated.</p>