function roundNumber(num, dec) 
{
    return Math.round(num*Math.pow(10,dec))/Math.pow(10,dec);
}

    function round2(num) 
    {
	return roundNumber(num, 2);
    }

    function recalc(x)
    {
	var B2 = document.getElementById('B2').value;
	var B3 = document.getElementById('B3').value;
	var C3 = document.getElementById('C3').value;
	var C3s = document.getElementById('C3s').value;

	if (B2=='')
	   B2 = 0;

   if (B3=='')
	      B3 = 0;

	      if (C3=='')
	      	 C3 = 0;

var B6 = 0;
var C6 = 0;
var B7 = 0;
var B8 = 0;
var C8 = 0;
var B9 = 0;
var B12 = 0;
var B16 = 0;

	if (x.id=='C3s' || C3=='_')
	{
	    if (C3s==25)
		B3 = 3;
	    if (C3s==40)
		B3 = 5;
	    if (C3s==60)
		B3 = 7;
	    if (C3s==75)
		B3 = 9;
	    if (C3s==100)
		B3 = 12;

	    document.getElementById('B3').value = round2(B3);

	    C3 = C3s;
	    if (C3=='vlastní')
	    {
		C3 = 100;
		document.getElementById('C3').className = 'recalc';

	    }
	    document.getElementById('C3').value = C3;

	}

	var B4 = document.getElementById('B4').value;
	var B5 = document.getElementById('B5').value;
	var B5s = document.getElementById('B5s').value;
	if (x.id=='B5s' || B5=='_')
	{
	    B5 = B5s;
	    if (B5=='vlastní')
	    {
		B5 = 5.40;
		document.getElementById('B5').className = 'recalc';
	    }
	    document.getElementById('B5').value = B5;
	}

	var B6 = document.getElementById('B6').innerHTML;
	var C6 = document.getElementById('C6').innerHTML;
	var B8 = document.getElementById('B8').innerHTML;
	var C8 = document.getElementById('C8').innerHTML;
	var B9 = document.getElementById('B9').innerHTML;
	var B10 = document.getElementById('B10').value;
	var C10 = document.getElementById('C10').value;
	var B11 = document.getElementById('B11').value;
	var C11 = document.getElementById('C11').value;


	B6 = ((B2*B3*B4)*365)/1000;////
//	alert('xxx '+B2+'.'+B3+'.'+B4+'.');
	C6 = ((B2*C3*B4)*365)/1000;
//	alert(C6+'-'+B6);
	B7 = C6-B6;
//	alert(B7+'='+C6+'-'+B6);
	B8 = B6*B5;
	C8 = C6*B5;
	B9 = C8-B8;
	B12 = ((B10*B2)/B9)*365;
	B16 = ((B11/B4)/365)*B9;

	document.getElementById('B6').innerHTML = round2(B6);
	document.getElementById('C6').innerHTML = round2(C6);
	document.getElementById('B7').innerHTML = round2(B7);
	document.getElementById('B8').innerHTML = round2(B8);
	document.getElementById('C8').innerHTML = round2(C8);
	document.getElementById('B9').innerHTML = round2(B9);
	document.getElementById('B12').innerHTML = round2(B12, 1) + ' dní = cca ' + roundNumber(B12/30, 1) + ' měsíců = cca ' + roundNumber(B12/365, 1) + ' let';
	document.getElementById('B16').innerHTML = round2(B16);
    } 


    function startujem()
    {
	if (!document.getElementsByTagName)
	    return false;

	nalepit('input');
	nalepit('select');
    }

    function nalepit(tag)
    {
	var prvky = document.getElementsByTagName(tag);
	for (i=0;i<prvky.length;i++)
	    if (prvky[i].className.match("recalc"))
	        {
		   prvky[i].onkeyup = function () { return recalc(this); }
		   prvky[i].onchange = function () { return recalc(this); }
		}
    }
    window.onload = startujem;