Hola
Quizás sea esto lo que te ocupa
Código Javascript
:
Ver original<html>
<head>
</head>
<body>
<script type="text/javascript">
function Suma(isChecked, valor){
if (isChecked) {
document.sumar1.siniva1.value = (parseFloat(document.sumar1.siniva1.value) + parseFloat(valor)).toFixed(2);
document.sumar1.coniva1.value = parseFloat(document.sumar1.siniva1.value * 0.16).toFixed(2);
} else {
document.sumar1.siniva1.value = parseFloat(document.sumar1.siniva1.value - valor).toFixed(2);
document.sumar1.coniva1.value = parseFloat(document.sumar1.siniva1.value * 0.16).toFixed(2);
}
document.sumar1.total1.value = (parseFloat(document.sumar1.siniva1.value) + parseFloat(document.sumar1.coniva1.value) + parseFloat(document.sumar1.totalactual.value)).toFixed(2);
}
</script>
<body>
<table border="1">
<tr>
<td>
<form name="sumar1" method="POST">
<p><b><font color="#999999">Importe Actual con IVA 16%</font></b> <input type="text" value="200.00" id="totalactual" name="totalactual" disabled /> €</p>
<p>Televisión LG <input type="checkbox" value="2000.00" id="Prod1" name="Prod1" onClick="Suma(this.checked,this.value)" />2000,00 €</p>
<p>Televisión Sony <input type="checkbox" value="1505.99" id="Prod2" name="Prod2" onClick="Suma(this.checked,this.value)" />1505,99 €</p>
<p>Televisión Panasonic <input type="checkbox" value="1151.99" id="Prod3" name="Prod3" onClick="Suma(this.checked,this.value)" />1151,99 €</p>
<input type="hidden" value="0.00" id="siniva1" name="siniva1" />
<input type="hidden" value="0.00" id="coniva1" name="coniva1" />
<p><b><font color="#999999">Importe Total con IVA 16%</font></b> <input id="pago" class="resultado" type="text" id="total1" name="total1" value="200" /> €</p>
</form>
</td>
</tr>
</table>
</body>
</html>
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