<form name="search" id="search" action="" method="post" accept-charset="utf-8">
  <input type="text" name="search[client]" id="searchclient" />
  <input type="text" name="search[ipaddr]" id="searchipaddr" />
...

<?php
function canlink() {
echo '<link rel="canonical" href="http://' . $_SERVER["HTTP_HOST"] . $_SERVER["REQUEST_URI"] . '" />';
...

$getvalues = array('id', 'page', 'var1, 'var2', 'var3');

foreach($getvalues as $getvalue)
...