function calc()
{

	var kedvezmeny = 0;
	var alap = 0;


	for (var i = 0; i < document.forms[0].elements.length; i++)
	{	
		if (document.forms[0].elements[i].checked) 
		{
			if (alap > 0) kedvezmeny += (prices[i][1] - prices [i][2]);	
			alap+= prices[i][0]+  prices[i][1];
		}	
	}


	var sum = alap - kedvezmeny;

	
	document.forms[0].price.value = alap;
	document.forms[0].discount.value = kedvezmeny;
	document.forms[0].sum.value = sum;

}




/*
document.write('Alap:<input type = textbox name = "tb1"><br>');
document.write('Megtakarítás:<input type = textbox name = "tb2"><br>');
document.write('Összesen:<input type = textbox name = "tb3"><br><br>');
*/