var price_e85=230, price_petrol=330, add_cons=20, avg_cons=8, mileage=15000, price_inst=49900, save=0, cons_petrol=0, cons_e85=0;

function klikk() {	
	if ((document.getElementById('price_e85').value == '0') ||
		(document.getElementById('price_petrol').value == '0') ||
		(document.getElementById('add_cons').value == '0') ||
		(document.getElementById('avg_cons').value == '0') ||
		(document.getElementById('mileage').value == '0') ||
		(document.getElementById('price_inst').value == '0')) { alert('Sehol sem lehet 0!');
	} else {		
		price_e85 = document.getElementById('price_e85').value*1;
		price_petrol = document.getElementById('price_petrol').value*1;
		add_cons = document.getElementById('add_cons').value*1;
		avg_cons = document.getElementById('avg_cons').value*1;
		mileage = document.getElementById('mileage').value*1/100;
		price_inst = document.getElementById('price_inst').value*1;				
		cons_petrol = mileage * price_petrol * avg_cons;
		cons_e85 = mileage * price_e85 * avg_cons*((100+add_cons)/100);		
		save = cons_petrol - cons_e85;		
		document.getElementById('cons_petrol').value = cons_petrol;
		document.getElementById('cons_e85').value = cons_e85;
		document.getElementById('save').value = save;		
		document.getElementById('time').value = Math.round(price_inst/save*12);
	}
}