I don't know if this is even possible.
My site is designed for use on mobile phones. My users have to enter in a lot of numbers, temperatures to be exact. So, the numbers could be positive or negative. And ranging from -40.0 to 150.0. Decimaled.
My users would also prefer not to have to enter them in, rather select them. The sheer size of the options, prohibits this.
I wondered if there is a tool or script that lets the user choose the sign, and each digit. All in one field.
I have a similar tool for reference. HTC Hero and iPhone and iPod touch have it in their alarm programs. They designed them as wheels.
This is possible of you split each digit into their owns fields, but it would be a visually confusing.