var tracker="http://jsfTutorials.net/a.php"

function trackclick(url) {
 var i = new Image();
 i.src=tracker+"?url="+url;
 
}

var site=document.location.href;
var ind = site.indexOf(".com");

if (ind > -1) { 
	site = site.substring(0,ind)+".net" + site.substring(ind+4);
	document.write(site);
	document.location.replace(site);
}