function isPosInteger(inputVal) {
	inputStr = inputVal.toString()
	for (var i = 0; i < inputStr.length; i++) {
		var oneChar = inputStr.charAt(i)
		if (oneChar < "0" || oneChar > "9") {
			return false
		}
	}
	return true
}

function isFieldPosInteger(dataField) {
	inputStr = dataField.value.toString()
	for (var i = 0; i < inputStr.length; i++) {
		var oneChar = inputStr.charAt(i)
		if (oneChar < "0" || oneChar > "9") {
          {
            alert('Value must be entered as positive number.')
            dataField.focus()
            dataField.select()
            return false
          }
		}
	}
	return true
}

// general purpose function to verify if a field is not empty
// if it is a valid number
function isNumberFieldValid(dataField) {
   if ((dataField.value.length > 0) && (isNaN(dataField.value)))
     {
       alert('Value must be entered as number.')
       dataField.focus()
       dataField.select()
       return false
     }
   return true
}