<?php
$message = 'choukai kai';
$lowercasemessage = strtolower($message);
$replacedwords = array('surfing', 'joke and stuff', 'smile and etc', '3-2', 'choukai kai', 'choukai');
$message = str_ireplace(
$replacedwords,
array(
// here all replaces | each in a new line - watch the syntax
// all html possible, but no single quotation mark!
'<a href="http://en.wikipedia.org/wiki/Surfing" style="color:darkred;font-weight:bold;">surfing</a>',
'<a href="http://en.wikipedia.org/wiki/Joke" style="color:darkred;font-weight:bold;">joke</a>',
'<a href="http://en.wikipedia.org/wiki/Smiling" style="color:darkred;font-weight:bold;">Smile</a>',
'<a class="screenshot" rel="3-2_Map.jpg">3-2</a>',
'<a href="http://en.wikipedia.org/wiki/Joke" style="color:darkred;font-weight:bold;">Choukai Kai</a>',
'<a href="http://en.wikipedia.org/wiki/Smiling" style="color:darkred;font-weight:bold;">Choukai</a>'
),
$message);
echo $message;