// function isZipCode verifies that all digits/characters are numeric
// Call it like this
// if(!isZipCode(prod.productprice.value)
function isZipCode(inputVal) {
	oneDash = false
	inputStr = inputVal.toString()

	if(inputStr.length < 5) { // return false if null string
		return false
	}
	for (var i = 0; i < inputStr.length; i++) {
		var oneChar = inputStr.charAt(i)
		if(oneChar == "-" && !oneDash) {  // this verifies there is only one decimal in the string
			oneDash = true				 // all looks good so continue
			continue
		}
		if(oneChar < "0" || oneChar > "9") { // return false if any of the characters are
			return false					 // non-numeric
		}
	}
	return true // yes, it is a true number.
} // END function isZipCode(inputVal)