Javasript help

Hi,

Can I clarify what you want to happen.

Starting point of document

[box1 hidden]

box2 has no value

box3 = ????

Then the user enters a value in box2

box1 = 500

box2 = 10

box3 = 490

So the key parts are what does box3 equal when box1 is hidden, as hidden just means the user can't see it?

As validation script of box2 use this:

this.getField("box1").value = event.value != "" ? 500 : "";