function phoneFormat(number) {
	var phonenumber = number.value;
	var formattednumber = "";
	
	for (var i = 0; i < phonenumber.length; i++) {
		var ch = phonenumber.substring(i, i + 1);
		var valid = /^([0-9]*)$/.test(ch);
		if (valid) {
			formattednumber = formattednumber + '' + ch;
		}
	}
	
	if (formattednumber.length >= 10) {
		formattednumber = formattednumber.substring(0, 3) + "-" + formattednumber.substring(3, 6) + "-" + formattednumber.substring(6);
	}
	
	number.value = formattednumber;
	return;
}