var ref = document.referrer;

var multichannel_parent_url = document.URL;
var split_url = multichannel_parent_url.split('/');

site_domain = split_url[2];

document.write('<iframe src="http://www.multichannelgaming.com/banner_ga_sender.php?idaffiliation=104072&amp;idbanner=843&amp;ref='+ref+'&site_domain='+site_domain+'" name="multichannel_frame" style="display:none; width:1px; height:1px"></iframe>');