preg_replace() substrings NOT IN tags

Hi, I'm trying to figure out a regex that would match substrings in a string that are NOT inside tags. In the example below I try to replace the substring 'paris' with <a href=\"http://www.somehost.com">paris</a> but it also matches 'paris' in the image name. * this does not work: $url = "http://www.somehost.com"; $needle = "paris"; $haystack = "<img src=\"/images/3_im_paris_tower.jpg\"> paris trip"; $regex="($needle).*?[^>]"; echo preg_replace ("/$regex/", "<a href=\"$url\">\\1</a> ",$haystack); An even simpler example of what I am trying to do is as follows: Match 'a' in the following string if it is followed by ( zero or more of *any* character, then NOT a '>' ) * this does not work ( using regex ASSERTIONS ) * it matches the 'a' before the '>' ... which I don't want ) $haystack = "ad>bc|abc "; $regex="(a(?=.*?)(?!>))"; Thanks in advance for your help, Bruce _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp