var url = "http://netduster.com/mtracking.asp";
var querystring = document.location.search;

if (querystring==null || querystring=="")
	{	
		var url = url+custom;
		document.write('<div style="padding:-11px 0px 0px 0px"><img name=click src='+url+' width=0 height=0></div>')
	}
else 
	{
		var url = url+querystring;
		document.write('<div style="padding:-11px 0px 0px 0px"><img name=click src='+url+' width=0 height=0></div>')
	}