function calculation() {
	var d = document;
	var pwr_sel = d.getElementById('power_rating_2');
	var pwr = pwr_sel[pwr_sel.selectedIndex].value
	d.getElementById('power_rating_1').innerHTML = pwr/5;

	var kvt = d.getElementById('kvt').value;
	var cost_1 = pointify(d.getElementById('cost_1').value);
	//if (cost_1==0) return;
	var cost_2 = pointify(d.getElementById('cost_2').value);
	//if (cost_2==0) return;
	if (cost_1==0) cost_1 = 130;
	if (cost_2==0) cost_2 =   7;
	d.getElementById('cost_1').value = cost_1;
	d.getElementById('cost_2').value = cost_2;
	var life_time_1 = d.getElementById('life_time_1').value;
	var life_time_2 = 1000;
	if (life_time_1==0) life_time_1 = 8000;
	d.getElementById('life_time_1').value = life_time_1;
	d.getElementById('life_time_2').innerHTML = life_time_2;
	var eko_1 = -cost_1+(cost_2*(life_time_1/life_time_2))
		d.getElementById('eko_1').innerHTML = trimTo2(eko_1);
	var eko_2 = (4*pwr/5)*kvt;
		d.getElementById('eko_2').innerHTML = trimTo2(eko_2);
	var eko_3 = eko_2*(life_time_1/life_time_2);
		d.getElementById('eko_3').innerHTML = trimTo2(eko_3);
	var itogo = eko_1+eko_3;
		d.getElementById('itogo').innerHTML = trimTo2(itogo);
}
function pointify(val) {
	val = val.replace(/,/,'.')
	if (/\.$/.test(val)) {
		val += '0'
	}
	return val
}
function trimTo2(val) {
	var v = new Array();
	v = val.toString().split('.');
	if (v.length>1) {
		v[1] = v[1].substr(0,2)
		val = v.join('.')
	}
	return val
}
calculation();