// JavaScript Document

function calc() 
{
	
	var totalEmissions = 0;
	
	for (var i=1;i<=8;i++)
	{
		// number of cars in band
		var ni = "NO_" + i;
		var n = document.form1.elements[ni].value;
		
		// emissions
		var co2i = "CO2_" + i;
		var CO2 = document.form1.elements[co2i].value;
		
		// estimated yearly mileage of cars in band
		var mi = "M_" + i;
		var m = document.form1.elements[mi].value;
		
	
		// Convert Miles to Kilometres (1m = 1.609344 kilometres)
		var km = m * 1.609344;
			
		// Multiply CO2 Emissions by Kilometres
		CO2 = CO2 * km;
	
		// Add Real World Factor (15% uplift)
		CO2 = CO2 * 1.15;
	
		// Divide by 1,000,000 to get the tonnes of CO2 Generated each year
		CO2 = CO2 / 1000000;
		
		// Multiply CO2 by number of cars
		CO2 = CO2 * n;
		
		totalEmissions = Number(totalEmissions) + Number(CO2);
		
		document.getElementById("carbonFootprint").innerHTML = totalEmissions.toFixed(2);
	}
	
}