function ShowArrow(id) {
/*	if (typeof document.getElementById == 'function') {
		document.getElementById(id).style.background = 'url(/i/arrow.gif) no-repeat  50% 100%';
	} else if (document.all) {
		document.all[id].style.background = 'url(/i/arrow.gif) no-repeat  50% 100%';
	}*/
}

function HideArrow(id) {
	/*
	if (typeof document.getElementById == 'function') {
		document.getElementById(id).style.background = 'url(/i/v.gif) no-repeat  50% 100%';
	} else if (document.all) {
		document.all[id].style.background = 'url(/i/v.gif) no-repeat  50% 100%';
	}*/
}





function Calculator() {
	benefit = document.getElementById('benefit').value;
	years = document.getElementById('years').value;
	invest = document.getElementById('invest').value;
	total = benefit*years /(1 + years*0.2) - invest;
	document.getElementById('val').innerHTML = Math.round(total);
}

function isNumType(v) {
	var c = typeof(v);
//	alert (c);
	if (c == 'number') {
		return true;
	} else {
		return false;
	}
}