Uffff me has pillado con ganas....
Código HTML:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Documento sin título</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script language="JavaScript" type="text/JavaScript">
function calcula(obj){
var hilos;
var iva;
var preciohilo;
if (obj.value.length!=0 && !isNaN(obj.value)){
hilos=parseFloat(obj.value);
if (document.getElementById("preciohilo").value.length!=0
&& !isNaN(document.getElementById("preciohilo").value)){
preciohilo=parseFloat(document.getElementById("preciohilo").value);
}else{
preciohilo=0;
alert("Precio unitario igual a cero?");
}
document.getElementById("totalx").innerHTML=format_number(parseInt(preciohilo * hilos*100+.5,10)/100,2);
if (document.getElementById("tpiva").value.length!=0
&& !isNaN(document.getElementById("tpiva").value)){
iva=parseFloat(document.getElementById("tpiva").value)/100;
}else{
iva=0;
alert("IVA igual a cero?");
}
document.getElementById("subtotal").innerHTML=format_number(parseInt(preciohilo * hilos*100+.5,10)/100,2);
document.getElementById("iva").innerHTML=format_number(parseInt((preciohilo * hilos)*iva*100+.5,10)/100,2);
document.getElementById("total").innerHTML=format_number(parseInt((preciohilo * hilos)*(1+iva)*100+.5,10)/100,2);
}
}
function format_number(pnumber,decimals){
if (isNaN(pnumber)) { return 0};
if (pnumber=='') { return 0};
var snum = new String(pnumber);
var sec = snum.split('.');
var whole = parseFloat(sec[0]);
var result = '';
if(sec.length > 1){
var dec = new String(sec[1]);
dec = String(parseFloat(sec[1])/Math.pow(10,(dec.length - decimals)));
dec = String(whole + Math.round(parseFloat(dec))/Math.pow(10,decimals));
var dot = dec.indexOf('.');
if(dot == -1){
dec += '.';
dot = dec.indexOf('.');
}
while(dec.length <= dot + decimals) { dec += '0'; }
result = dec;
} else{
var dot;
var dec = new String(whole);
dec += '.';
dot = dec.indexOf('.');
while(dec.length <= dot + decimals) { dec += '0'; }
result = dec;
}
return result;
}
</script>
</head>
<body>
<form id="form2" name="form2" method="post" action="">
<table border="0" cellspacing="0" cellpadding="0" style="font-size:11px; color:#000;">
<tr>
<td width="215" valign="top"><p><span class="rows">SERVICIO</span></p></td>
<td width="104" valign="top"><p><span class="rows">PRECIO</span></p></td>
<td width="134" valign="top"><p><span class="rows">CANTIDAD DE HILOS</span></p></td>
<td width="183" valign="top"><p><span class="rows">TOTAL ($70 X NUM DE HILOS)
</span></p></td>
</tr>
<tr>
<td width="215"><p><span class="rows">Instalación de colgante por hilo</span></p></td>
<td width="104"><p align="center"><span class="rows">$
<input name="hilos" type="text" id="preciohilo" size="8" value="70.00" onKeyUp="calcula(document.getElementById('hilos'))"/>
x hilo</span></p></td>
<td width="134" valign="top"><p>
<label>
<input name="hilos" type="text" id="hilos" size="5" onKeyUp="calcula(this)"/>
</label>
</p></td>
<td width="183" valign="top" id="totalx" align="right">0</td>
</tr>
<tr>
<td colspan="4" valign="top"><p><span class="rows">Descripción :</span></p></td>
</tr>
<tr>
<td colspan="4" valign="top"><p><span class="rows">Cantidad de colgantes:</span></p></td>
</tr>
<tr>
<td colspan="3" align="right"><span class="rows">Precios mas I.V.A.</span></td>
<td width="183" valign="top" align="right"><input name="hilos" type="text" id="tpiva" size="5" value="15" onKeyUp="calcula(document.getElementById('hilos'))"/>
%</td>
</tr>
<tr>
<td colspan="3" valign="top"><p align="right"><span class="rows">SUB-TOTAL</span></p></td>
<td width="183" valign="top" id="subtotal" align="right">0</td>
</tr>
<tr>
<td colspan="3" valign="top"><p align="right"><span class="rows">IVA</span></p></td>
<td width="183" valign="top" id="iva" align="right">0</td>
</tr>
<tr>
<td colspan="3" valign="top"><p align="right"><span class="rows">TOTAL</span></p></td>
<td width="183" valign="top" id="total" align="right">0</td>
</tr>
</table>
</form>
</body>
</html>
Quim