url = document.location.href ;
partes = url.split('/');
//alert(partes.length);
//alert(partes[3]); 



var script = document.createElement('script');
script.type = 'text/javascript';
if ((partes.length > 4) && HASObject.fileExist('/js/'+partes[3]+'.js')){
	script.src = '/js/'+partes[3]+'.js';
	}
else{
	script.src = '/js/principal.js';
}

//alert (script.src);
document.getElementsByTagName('head')[0].appendChild(script);