ogame trade calculation

<table>
<tr>
<td>What are you selling:(M,C,D)<input type="text" maxlength="1"/></td>
</tr><tr>
<td>How much of that:<input type="number" id="howMuch" /></td>
</tr><tr>
<td>ratio of the two things you whish to get:<input id="A" type="number"><input id="B" type="number"></td>
</tr><tr>
<td>ratios:(something:something:what your selling)<input id="M" type="number" /><input id="C" type="number" /><input id="D" type="number" /></td>
</tr><tr><td>
<input type="button" onclick="calculate()" value="Calculate" />
</td></tr><tr>
<td>Amounts you will get: <x id="amount1"></x>:<x id="amount2"></x></td></tr>
</table>
<script>
function calculate(){
//get amount
var H = document.getElementById('howMuch').value;
//get rates
var C = document.getElementById('M').value;
var D = document.getElementById('C').value;
var E = document.getElementById('D').value;
//get ration of buying
var A = document.getElementById('A').value;
var B = document.getElementById('B').value;
var G = H*C*D;
var AB = A/B;
var DC = Number(D)+Number(C);
G = 2*G/(E*(AB+1)*(DC));
var F = AB*G;
document.getElementById('amount1').innerHTML = F;
document.getElementById('amount2').innerHTML = G;
}
</script>