simplekolecalc/kole.html

<!DOCTYPE html>
<html>
<head>
<style>
	input[type='number']{text-align:right;}
</style>
</head>
<body>
   <h1>Rechner zwischen Brutto-Netto-Kole</h1>
	<table>
		<tr><td>Eingangsgröße:</td><td><input type="radio" name="b" value="e" id="bb" class="bb" checked="checked"/><label for="bb">Brutto</label><input type="radio" name="b" value="b" id="bn" class="bb"/><label for="bn">Netto</label><input type="radio" name="b" value="k" id="bk" class="bb"/><label for="bk">KoLe</label></td></tr>
		<tr><td>Brutto</td><td><input type="number" step="0.01" id="e" value="100.00"/>&thinsp;€</td></tr>
		<tr><td>Umsatzsteuersatz</td><td><input type="number" step="0.01" id="u" value="19.00"/>&thinsp;%</td></tr>
		<tr><td>Umsatzsteuer</td><td><input type="number" step="0.01" id="us" value="0.00"/>&thinsp;€</td></tr>
		<tr><td>Netto</td><td><input type="number" step="0.01" id="n" value="0.00"/>&thinsp;€</td></tr>
		<tr><td>Entropieumlagesatz</td><td><input type="number" step="0.01" id="z" value="23.00"/>&thinsp;%</td></tr>
		<tr><td>Entropieumlage</td><td><input type="number" step="0.01" id="eu" value="23.00"/>&thinsp;€</td></tr>
		<tr><td>KoLe</td><td><input type="number" step="0.01" id="k" value="0.00"/>&thinsp;€</td></tr>
		<tr><td>&nbsp;</td><td><input value="Berechnen" id="b" type="button"/></td></tr>
	</table>
	<script>
		var e=document.getElementById('e');
		var u=document.getElementById('u');
		var us=document.getElementById('us');
		var n=document.getElementById('n');
		var z=document.getElementById('z');
		var eu=document.getElementById('eu');
		var k=document.getElementById('k');
		var bb=document.getElementById('bb'); 
		var bn=document.getElementById('bn'); 
		var bk=document.getElementById('bk'); 
		var s = document.getElementById('b');

		function getFormFloat(f){
			return parseFloat(f.value);
		}
		function roundCents(f){
			return Math.round( f * 100 ) / 100;
		}

		s.addEventListener('click', function(){
			if(bk.checked){
				e.value = roundCents( getFormFloat(k) * ( 1 + getFormFloat(u) / 100 ) / ( 1 - getFormFloat(z) / 100 ) );
				n.value = roundCents( getFormFloat(k) / ( 1 - getFormFloat(z) / 100 ) );
			}else if(bb.checked){
				k.value = roundCents( getFormFloat(e) / ( 1 + getFormFloat(u) / 100 ) * ( 1 - getFormFloat(z) / 100 ) );
				n.value = roundCents( getFormFloat(e) / ( 1 + getFormFloat(u) / 100 ) );
			}else if(bn.checked){
				e.value = roundCents( getFormFloat(n) * ( 1 + getFormFloat(u) / 100 ) );
				k.value = roundCents( getFormFloat(n) * ( 1 - getFormFloat(z) / 100 ) );
			}
         us.value = roundCents(e.value * getFormFloat(u) / 100 );
         eu.value = roundCents(n.value * getFormFloat(z) / 100 );
		});
		e.addEventListener('change', function(){bb.checked = true;});
		n.addEventListener('change', function(){bn.checked = true;});
		k.addEventListener('change', function(){bk.checked = true;});
		s.click();
	</script>
</body>
</html>