Nulla non va ora mi ritrovo con:

<SCRIPT type=text/JavaScript src="Calculator.js"></SCRIPT>

<TABLE class="formC" cellSpacing="0" cellPadding="3" border="0">
<FORM name="frmCalculator" onSubmit="return calculator();" method="post" action="property-investment-opportunities.html" >
<TD align="left">Your house is worth:
</TD>
<TD >£
<INPUT style="WIDTH: 100px" name="strsmv">
</TD>
</TR>
<TR>
<TD align="center" colspan="2" class="nd">
Now detuct
</TD>
</TR>
<TR>
<TD align="left">
Typical offer from possible buyer:
</TD>
<TD>
<SELECT name="strtypicaloffer">
<OPTION value="" selected>Please select...</OPTION>
<OPTION value="0">7</OPTION>
<OPTION value="1">8</OPTION>
</SELECT>%
</TD>
</TR>
<TR>
<TD align="left">
Approx Fee to Estate Agent:
</TD>
<TD>
<SELECT name="strfeeEA">
<OPTION value="" selected>Please select...</OPTION>
<OPTION value="0">2</OPTION>
<OPTION value="1">2.5</OPTION>
</SELECT>%
</TD>
</TR>
<TR>
<TD align="left">Legal fees (approx):
</TD>
<TD >£
<INPUT style= "width:100px" name="strfl" value="500">
</TD>
</TR>
<TR>
<TD align="left">Interest cost on 6 moths:
</TD>
<TD >£
<INPUT style="WIDTH: 100px" name="stricms">
</TD>
</TR>


<TR>
<TD>
<INPUT class="bttn" type="reset" value="Reset" name="Reset">
</TD>
<TD>
<INPUT class="bttn" type="submit" value="Send" name="Submit">
</TD>
</TR>
<TR>
<TD align="left">Real value of an Estate Agent Sale:
</TD>
<TD >£
<INPUT style="WIDTH: 100px" name="strtotalEA">
</TD>
</TR>
</FORM>
</TABLE>

e il javascript esterno
// JavaScript Document
editabile=false;
function calculator() {
//Var
var smv = document.frmCalculator.strsmv.value;
var to = document.frmCalculator.strtypicaloffert.value;
var tot = ""
var fea = document.frmCalculator.strfEA.value;
var legalfee = document.frmCalculator.strelf.value;
var icms = document.frmCalculator.stricms.value;
var feat = ""
var totea = ""

send=true;
// script for your house is worth
if ((smv == "") || (smv == "undefined")) {
alert(" Please insert a Estate Agent's suggested market value for your house");
document.frmCalculator.strsmv.focus();
send=false;
return send;
}
// script for Typical offer from possible buyer
if ((to == 7)) {
tot = smv - (smv / 100 * 7)
}
else{
tot = smv - (smv / 100 * 8)
}
//script fee to Estate Agent
if ((to == 2)) {
tot = smv - (smv / 100 * 2)
}
else{
tot = smv - (smv / 100 * 2.5)
}
//script for real value

if ((totea == 0)) {
totea = smv - tot - feat - legalfee - icms;
document.frmCalculator.strtotalEA.value = totea;
}
}//end function