{source}
<iframe id="heizungsfinder-widget" src="http://www.heizungsfinder.de/extern/index/provider/pelletsbestellung-de/?css=http://test.pelletsbestellung.de/templates/pellets/css/heizungsfinder.css" width="590" height="900" scrolling="auto" frameborder="0" /></iframe>
<script type="text/javascript">
(function () {
var match = document.URL.match(/(\?|&)plz=([0-9]+)/);
if(match != null) {
var w = document.getElementById('heizungsfinder-widget');
var f = w.src.split('?');
w.src = f.length == 2 ? (f[0] + '/zipcode/' + match[2]+"?"+f[1]):(f[0] + '/zipcode/' + match[2]);
}
})();
</script>
{/source}