scanning text input

[demonicfoetus]

Hi, i've seen this done on other sites but i haven't been able to work it out my self. so i'll ask. When a user enters some text into a form, i want the script to scan the text for certain words and then take appropirate action i.e. replacing the word. So in effect a bad word filter. What functions do i need to use to do this? Example code would be greatly appreciated. Thanks, in advance.
-DF

[stolzyboy]

well i'd start at looking into the string functions

[Pig]

function word_filter($string)
{
     $words = array(
          badword1 => "goodword1",
          badword2 => "goodword2",
          badword3 => "goodword3",
          badword4 => "goodword4",
          badword5 => "goodword5"
          );

 foreach( $words AS $key => $value )
 {
      $new_string .= str_replace($key, $value, $string);
 }
 return $new_string;
}

That will do a filter for naughty words. Add as many bad/good combinations that you want.