function enviarA(tipus) {
	
	var title = encodeURIComponent(window.document.title);
	var href = encodeURIComponent(window.document.location.href);

	switch(tipus) {
		case 'facebook' : desti = 'http://www.facebook.com/share.php?u=' + href; break;
		case 'twitter' : desti = 'http://twitthis.com/twit?url=' + href + '&title=' + title; break;
		case 'linkedin' : desti = 'http://www.linkedin.com/shareArticle?mini=true&url=' + href + '&title=' + title + '&summary=&source='; break;
	}

	window.open(desti);
	
}