BAN words, number and emails in a text area

Hi, Please find the attatched [login to view URL] file i wish to add code to the text area which will ban specific words, numbers and emails of my chocie, if the banned word is entered it can either redirect the user of display the word banned in the textarea and will not allow the user to proceed. So far people who have modified my code have been unable to sort it and it stops the full scrip from working, please can someone do this task asap!