function setCo(event) {
	var dec_point     = ',';
	var thousands_sep = '.';

	var error = false;

	var result1 = 0;
	var result2 = 0;
	var result3 = 0;

	var result1flug = 0;
	var result2flug = 0;
	var result3flug = 0;

	var result1bus = 0;
	var result2bus = 0;
	var result3bus = 0;

	var result1auto = 0;
	var result2auto = 0;
	var result3auto = 0;

	var value1 = document.getElementById('field1').value;
	var value2 = document.getElementById('field2').value;
	var value3 = document.getElementById('field3').value;

	var label1 = document.getElementById('field1label').innerHTML;
	var label2 = document.getElementById('field2label').innerHTML;
	var label3 = document.getElementById('field3label').innerHTML;

	// eingaben checken

	if (checkNumber(label1, value1, 'error1') == false) {
		error = true;
	}

	if (checkNumber(label2, value2, 'error2') == false) {
		error = true;
	}

	if (checkNumber(label3, value3, 'error3') == false) {
		error = true;
	}

	if (error != true) {

		// berechne flug

		if (value1 != "") {
			value1 = str_replace(',', '.', value1);
			value1 = str_replace(' ', '', value1);

			// co

			result1flug = calCo(value1, 1);

			// baum

			// result2flug = calBaum(value1, 1);

			// preis

			// result3flug = calPreis(value1, 1);
		}

		// berechne bus

		if (value2 != "") {
			value2 = str_replace(',', '.', value2);
			value2 = str_replace(' ', '', value2);

			// co

			result1bus = calCo(value2, 2);

			// baum

			//result2bus = calBaum(value2, 2);

			// preis

			//result3bus = calPreis(value2, 2);
		}

		// berechne auto

		if (value3 != "") {
			value3 = str_replace(',', '.', value3);
			value3 = str_replace(' ', '', value3);

			// co

			result1auto = calCo(value3, 3);

			// baum

			//result2auto = calBaum(value3, 3);

			// preis

			//result3auto = calPreis(value3, 3);
		}

		// co

		result1 = result1flug + result1bus + result1auto;
		result1 = number_format(result1, 0, dec_point, thousands_sep);

		// baum

		//result2 = result2flug + result2bus + result2auto;
		//result2 = number_format(result2, 0, dec_point, thousands_sep);

		// preis

		//result3 = result3flug + result3bus + result3auto;
		//result3 = number_format(result3, 0, dec_point, thousands_sep);

		// show result

		if (value1 != '' || value2 != '' || value3 != '') {
			
			document.getElementById('result1').innerHTML = result1;
			//document.getElementById('result2').innerHTML = result2;
			//document.getElementById('result3').innerHTML = result3;

			document.getElementById('result').style.display = 'block';
		}
	}
}

// co2 berechnen

function calCo(value, art) {
	switch (art) {
		case 1:
			var liter  = 5;		// liter auf 100 km
			var weight = 3.15;	// kg co2
		break;
		case 2:
			var liter  = 5;		// liter auf 100 km
			var weight = 2.3;	// kg co2
		break;
		case 3:
			var liter  = 2;		// liter auf 100 km
			var weight = 2.3;	// kg co2
		break;
	}

	return (value / 100) * liter * weight;
}

// baumanzahl berechnen

function calBaum(value, art) {
	var tree = 6;		// baueme pro kg

	return calCo(value, art) / tree;
}

// preis berechnen

function calPreis(value, art) {
	var price = 0.8;	// dollar pro baum

	return calBaum(value, art) * price;
}

// eingabe prüfen (inklusive ',.')

function checkNumber(label, value, target) {
	if (isNaN(parseFloat(value)) && value != "") {
		document.getElementById(target).style.display = 'block';

		return false;
	}
}