<?php
$add = array(
'utm_source'=>'edm',
'utm_medium'=>'email',
'utm_campaign'=>'product_notify');
$doc = new DOMDocument();
$doc->loadHTML('First Link <a href="http://www.google.com">no param</a><br />
Second Link <a href="http://www.google.com/">no param with /</a><br />
Third Link <a href="http://www.google.com?query=one">one param</a><br />
Fourth Link <a href="http://www.google.com?query=one&q2=two">two param</a><br />');
foreach($doc->getElementsByTagName('a') as $link){
$url = parse_url($link->getAttribute('href'));
$params = array();
if (isset($url['query'])) {
parse_str($url['query'], $params);
}
$gets = array_merge($params, $add);
$newstring = '';
if(isset($url['scheme'])) $newstring .= $url['scheme'].'://';
if(isset($url['host'])) $newstring .= $url['host'];
if(isset($url['port'])) $newstring .= ':'.$url['port'];
if(isset($url['path'])) $newstring .= $url['path'];
$newstring .= '?'.http_build_query($gets);
if(isset($url['fragment'])) $newstring .= '#'.$url['fragment'];
$link->setAttribute('href',$newstring);
}
$html = $doc->saveHTML();
echo $html;