Captcha with JavaScript

You've seen this. You must enter the above characters to submit a form.
This is to stop the bots that scour the net looking for forms they can spam. A robot can't read the text... a human can.
This is an easy script you can plug into your forms and have captcha validation without having to install server software or hack complex code.
A very nice solution.
Added Thursday 31 May, 2007.