web form question.

[Whiternoise]

Hey,

what sort of code would i need to make a form field update as the user is typing in info
example:

field1: user enters a number
field2: "
field3: "

field4: adds the results of 1, 2 and 3 and displays in realtime.

thanks for any advice, i think there's probably a javascript solution, but i can't find one.
Whiternoise

EDIT: oh, and i need to make sure that it doesn't interfere with a POST command in the form.

[yamangman]

Yea a client side scripting language quite obviously. If you're suggesting you can't find a suitable example then, well, you're not looking hard enough

[luap.h]

you'll need to attach a javascript function so that anytime field1-3 change, field 4 is calculated

<input name="field1" onchange="doCalculate();" />

function doCalculate()
{
total = document.form.field1.value + document.form.field2.value + document.form.field3.value;
document.form.field4.value = total;
}

something like that

[Whiternoise]

Cheers, much appreciated, and it's not that i don't look hard enough, it's just that i didn't know quite the name for the script that i was searching for (if you see what i mean )