Hello,
i am creating a funtion to calculate the vat and want to get the value ex vat
from a field and return the value including vat to another text field on the
same form.
Because the number of form elements will vary according to user action i need
to pass the form fields name to collect the value and return the result.
This is working fine to collect the value but I am stuck to return the new
value, here is the code i am using:

Tha function is called from the form with:
getVAT('field_name1','filed_name2')


function getVAT(from,to)
{
//collect the value from the form
var price = parseFloat(eval('document.form1.'+from+'.value'));



var incVat = price + (price * 21 / 100);

//return the value
eval('document.form1.'+to+'.value') = incVat;


}

Thanking you in advance
Olivier

Hi Olivier,

try referencing the form by elements

your code: eval('document.form1.'+to+'.value') = incVat;
change to: document.form1.elements[to].value = incVat;

hope this helps