codice:
</td>
<td><input onkeypress="onlynumers(this)" onkeyup="onlynumbers(this)" size="8" onchange="calculate()" name="altezza1"></td> 
<td><input onkeypress="onlynumers(this)" onkeyup="onlynumbers(this)" size="8" onchange="calculate()" name="larghezza1"></td> 
<td><input type="hidden" size="2" value="0.00" name="totalfin1"><input disabled="disabled" size="2" value="0.00" name="totalfin1"></td>
<td>[img]../images/euro.png[/img]</td> 
<td><input disabled="disabled" size="5" value="0.00" name="total1"></td> 
<td></td>
</tr>
Facendo cosi il campo total1 e NaN poiche il campo totalfin1 e utilizzato per svilupparlo,

codice:
document.calcform.total1.value = dp(((document.calcform.totalfin1.value)*prezzomq))