How can I Disable a Form Field?

**SKP** · 01-10-2008, 01:04 PM

Hi,
I know how to disable a field if a checkbox is checked, but I need to disable it if another text field has a "0" in it. For instance...
Let's say I have 2 fields - bikes and redbikes.
If I say I have 2 bikes I want to know how many are red. But if I have "0" bikes, I want to disable the redbikes field (since I already know I have no red bikes).
Can anyone give me an idea how to do this?
Thanks for your thoughts.

**chrishirst** · 01-10-2008, 02:42 PM

if (document.formname.bikes.value == 0) {
document.formname.redbikes.disabled = true;
}

**SKP** · 01-10-2008, 04:19 PM

Where do you call the function from, bikes? And how? By OnFocus or OnChange?
Sorry I'm so dumb about this. I'm trying to teach myself this stuff. And I've seen lots of different ways to call functions.

**chrishirst** · 01-11-2008, 03:18 AM

it all depends on how the text field is populated.