var elecfact = 0.43; // electricity conversion factor
var eleccpu = 1.00; // electricity cost per unit

var elecfact2 = 0.43; // electricity conversion factor
var eleccpu2 = 1.00; // electricity cost per unit

var elecfact3 = 0.43; // electricity conversion factor
var eleccpu3 = 1.00; // electricity cost per unit

var elecfact4 = 0.43; // electricity conversion factor
var eleccpu4 = 1.00; // electricity cost per unit

var carfact = 0.21; // car conversion
var airfact = 0.87; // air conversion
var treefact = 1.00; // tree conversion
var treefact2 = 1.00;
var treefact3 = 1.00;
var treefact4 = 1.00;
var treefact5 = 1.00;

function grandchange() {

    var f = document.grand;

    var total = 0;
    var n;

    f.house.value = total;
    
    total = Math.round(total / f.people.value);

    f.phouse.value = total;
    
    n = document.car.mass.value * 1;
    f.cartot.value = n;
    total += n;

    n = document.travel.mass.value * 1;
    f.traveltot.value = n;
    total += n;

    f.personal.value = total;

    f.mass.value = total;
    f.tonnes.value = total / 1000;
}

function carchange() {

    var f = document.car;
    
    var miles = f.motlast.value - f.motprev.value;
    
    f.miles.value = miles;

    var total = miles * f.share.value;

    f.total.value = total;

    f.mass.value = total * carfact;
	
    f.test.value = Math.round(total * carfact * treefact / 1000);

    grandchange();
}

function elecmeterchange() {
	
    var f = document.elecmeter;
	
    var cpy = f.cpw.value * 10;

    f.cpy.value = cpy;

    var units = Math.round(cpy * eleccpu);

    f.totalnew.value = units;
    f.mass.value = Math.round(units * elecfact);

    grandchange();
}

function elecmeterchange2() {
	
    var f = document.elecmeter2;
	
    var cpy = f.cpw.value * 0.5;

    f.cpy.value = cpy;

    var units = Math.round(cpy * eleccpu2);

    f.totalnew.value = units;
    f.mass.value = Math.round(units * elecfact2);

    grandchange();
}

function elecmeterchange3() {
	
    var f = document.elecmeter3;
	
    var cpy = f.cpw.value * 8.3;

    f.cpy.value = cpy;

    var units = Math.round(cpy * eleccpu3);

    f.totalnew.value = units;
    f.mass.value = Math.round(units * elecfact3);

    grandchange();
}

function elecmeterchange4() {
	
    var f = document.elecmeter4;
	
    var cpy = f.cpw.value * 10.056;

    f.cpy.value = cpy;

    var units = Math.round(cpy * eleccpu4);

    f.totalnew.value = units;
    f.mass.value = Math.round(units * elecfact4);

    grandchange();
}


function travelchange() {

    document.travel.mass.value
	= document.taxi.mass.value * 1
	+ document.train.mass.value * 1
	+ document.air.mass.value * 1;

    grandchange();
}

function airchange() {

    var f = document.air;

    var total = 0;

    var hours;
    var miles;

    hours = f.aira1.value * f.airb1.value;
    f.airc1.value = hours;
    miles = hours * 500;
    f.aird1.value = miles;
    miles *= f.aire1.value;
    f.airf1.value = miles;
    total += miles;

    hours = f.aira2.value * f.airb2.value;
    f.airc2.value = hours;
    miles = hours * 500;
    f.aird2.value = miles;
    miles *= f.aire2.value;
    f.airf2.value = miles;
    total += miles;

    hours = f.aira3.value * f.airb3.value;
    f.airc3.value = hours;
    miles = hours * 500;
    f.aird3.value = miles;
    miles *= f.aire3.value;
    f.airf3.value = miles;
    total += miles;

    hours = f.aira4.value * f.airb4.value;
    f.airc4.value = hours;
    miles = hours * 500;
    f.aird4.value = miles;
    miles *= f.aire4.value;
    f.airf4.value = miles;
    total += miles;

    hours = f.aira5.value * f.airb5.value;
    f.airc5.value = hours;
    miles = hours * 500;
    f.aird5.value = miles;
    miles *= f.aire5.value;
    f.airf5.value = miles;
    total += miles;

    hours = f.aira6.value * f.airb6.value;
    f.airc6.value = hours;
    miles = hours * 500;
    f.aird6.value = miles;
    miles *= f.aire6.value;
    f.airf6.value = miles;
    total += miles;

    hours = f.aira7.value * f.airb7.value;
    f.airc7.value = hours;
    miles = hours * 500;
    f.aird7.value = miles;
    miles *= f.aire7.value;
    f.airf7.value = miles;
    total += miles;

    hours = f.aira8.value * f.airb8.value;
    f.airc8.value = hours;
    miles = hours * 500;
    f.aird8.value = miles;
    miles *= f.aire8.value;
    f.airf8.value = miles;
    total += miles;

    f.total.value = total;
    f.mass.value = Math.round(total * airfact);

    travelchange();
}