function isNumeric(formInput) {
	var theString = formInput.value
	if ( ! theString.match(/^[-\d]+$/)) {
		alert('Please enter only numeric values')
		formInput.value = theString.length <= 1 ? '' : theString.substring(0, theString.length - 1)
		formInput.focus()
	}

	// return false	// never submit form on carriage-return
}