eregi help

I've made a link submitter to work on my site. So the users type in their site name and url, click submit and it gets added to the list. However, to prevent idiots from adding links to unpleasant content/pornography I've created a filter. It's a txt document with a bunch of words in it to disallow. The problem is this: $sitename = "xxx" That works fine. However, if someone uses: $sitename = "xxxforyou" It won't pick up the xxx part and disallow it. Is there a way to make sure it does pick up the "xxx" part? The code I'm using is: eregi ($sitename,$ono) $ono being the variable which stores the fgets of the text file with the words. To know how I can do this would be a great help, as I also have to block URLs that contain those words. Thanks in advance, Kris