Text Validation, Check for Zero

I have a text input box that needs to validate for a number between 0 and 11.75 (inches). At the same time, it needs to validate for no input.

I'm using:

if (Number(inches) > 11.75 || int(inches) == 0){
attachMovie("inchesError", "inchesError1", 10)
}

This does fine checking for an empty field, but it doesn't allow 0 to 3/4 inches.

Anyone know how to do both: check for no input and allow for numbers less than 1?

Thanks