UNIX script to check if httpd service is on or off and if off send a email : <p>Script to check if httpd is on or no</p>

<p>How do I make this script run in background so that it keeps checking if httpd service is on or off and emails a message if it goes off !! ( PS-: I DON'T WANT TO MAKE THE SCRIPT AS A CRONJOB) just like a daemon process which runs in background!!
               Please Help</p>
