function $_(n) {
	if(!n) return false;
	if(!document.getElementById(n)) return false;
	return document.getElementById(n)
}

/*--- e-mail ---*/
function mail(name, dom, a, display) {
	var m = "mailto:";
	document.write('<a href="'+m+name+'@'+dom+'.'+a+'">'+(display?display:name+'@'+dom+'.'+a)+'</a>');
}

/*--- plan ---*/
function swapImage(id, nr) {
	$('div.plan-description').css({ display:'none' });
	$('#plan_' + id + ' div.plan-description').css({ display:'block' });
	$_("plan4ik").style.backgroundPosition = "0 " + (-nr) + "px";
}
function restoreIMG() {
	$('div.plan-description').css({ display:'none' });
	$_("plan4ik").style.backgroundPosition = "0 0";
}