Hola
Phantasma__
A ver si esto te sirve:
Código HTML:
<html>
<head>
<script>
function sumar(frm) {
s1=parseInt(frm.sum1.value);
s2=parseInt(frm.sum2.value);
if(isNaN(s1)) s1=0;
if(isNaN(s2)) s2=0;
frm.total.value=s1+s2;
}
</script>
</head>
<body>
<form>
<input type="text" name="sum1" onkeyup="sumar(this.form)" />
<input type="text" name="sum2" onkeyup="sumar(this.form)" />
<input type="text" name="total" />
</form>
</body>
</html> Saludos,
