// Master value validator routine
function isValid(inputStr) {
	if (isEmpty(inputStr)) {
		alert("Please enter a number into the field before clicking the button.")
		return false
	} else {
		if (!isNumber(inputStr)) {
			alert("Please make sure entries are numbers only.")
			return false
		} else {
			if (!inRange(inputStr)) {
				var msg = "Sorry, the number you entered is not part of our database."
				msg += "Try another three-digit number."
				alert(msg)
				return false
			}
		}
	}
	return true
}
