Hi my name is Nick,
I have one question.
This example is ok, but i would like that the customers must be forced to use 50 and its multiply (EXAMPLE ONLY:50/100/150/200/250...):

function calculateText(){
var op1=document.getElementById('field1');
var op2=document.getElementById('field2');
var result=document.getElementById('Total');
if(op1.value=="" || op1.value!=parseFloat(op1.value)) op1.value=0;
if(op2.value=="" || op2.value!=parseFloat(op2.value)) op2.value=0;
result.value=0;
result.value=parseInt(result.value);
result.value=parseInt(result.value)+parseInt(op1.value)+parseInt(op2.value);}

and the total must be a part of the set of price

(EXAMPLE: from 50 to 300 the price is 1$
from 350 to 600 the price is 0,50 cent
from 650 to 1200 the price is 0,40 cent
and so on…)

Is it possible?

Thank you for your help!

Nick

I have risolved the problem.
this is the code:

if(op1.value=="" || op1.value!=parseFloat(op1.value) || op1.value%50!=0) op1.value=0;
if(op2.value=="" || op2.value!=parseFloat(op2.value) || op2.value%50!=0) op2.value=0;

instead of:

if(op1.value=="" || op1.value!=parseFloat(op1.value)) op1.value=0;
if(op2.value=="" || op2.value!=parseFloat(op2.value)) op2.value=0;

And in order to show the corresponding price in the Total field instead of the total of the calculation you will have to use a code line similar to the following one(with additional verifications for the rest of the values):

if(result.value>50 && result.value<300) result.value=1;

after the code line:

result.value=parseInt(result.value)+parseInt(op1.value)+parseInt(op2.value);

----
Thank's to technical support.

But I have another question.
Can I visualize the final price in every update windows?

EXAMPLE CODE:

<script type="text/javascript">
function calculateText()
{
var op1=document.getElementById('field1');
var op2=document.getElementById('field2');
var result=document.getElementById('Total');

if(op1.value=="" || op1.value!=parseFloat(op1.value)) op1.value=0;
if(op2.value=="" || op2.value!=parseFloat(op2.value)) op2.value=0;

result.value=0;
result.value=parseInt(result.value);
result.value=parseInt(result.value)+parseInt(op1.value)+parseInt(op2.value);
}
</script>