title: Create a Blacklist filter in a form to avoid some words
body: <p>I need to create a filter to avoid some websites to be submitted to my database. I want to do this to protect the content of my website against spammers.</p>
  
  <p>I have a regular form input text that is used to send a URL, I need some help to create a background action (in php maybe) that will check if this URL, that the user is trying to send, have some blacklisted words.</p>