/*****************************************************************************************************
	javascript form validation functions
*****************************************************************************************************/

// returns a string with spaces stripped from beginning and end
function trim(str) {
    return str.replace(/^\s+|\s+$/g,'');
} // trim

// returns true if the string is empty
function isEmpty(str){
	return (str == null) || (trim(str).length == 0);
} // isEmpty

// returns true if the string is a valid email
function isEmail(str){
	if (isEmpty(str)) return false;
	var re = /^[^\s()<>@,;:\/]+@\w[\w\.-]+\.[a-z]{2,}$/i;
	return re.test(str);
} // isEmail

// returns true if the string is a US phone number formatted as...
// (000)000-0000, (000) 000-0000, 000-000-0000, 000.000.0000, 000 000 0000, 0000000000
function isPhone(str) {
	var re = /^\(?[2-9]\d{2}[\)\.-]?\s?\d{3}[\s\.-]?\d{4}$/;
	return re.test(str);
} // isPhone

// returns true if the string only contains characters A-Z or a-z
function isAlpha(str){
	var re = /[^a-zA-Z]/g;
	if (re.test(str)) return false;
	return true;
} // isAlpha

// returns true if the string only contains characters 0-9
function isNumeric(str){
	var re = /[\D]/g;
	if (re.test(str)) return false;
	return true;
} // isNumeric

// returns true if the string only contains characters A-Z, a-z or 0-9
function isAlphaNumeric(str){
	var re = /[^a-zA-Z0-9]/g;
	if (re.test(str)) return false;
	return true;
} // isAlphaNumeric

// returns true if the string's length equals "len"
function isLength(str, len){
	return str.length == len;
} // isLength

// returns true if the string's length is between "min" and "max"
function isLengthBetween(str, imin, imax){
	return (str.length >= imin) && (str.length <= imax);
} // isLengthBetween

// returns true if the string is a valid date formatted as...
// mm dd yyyy, mm/dd/yyyy, mm.dd.yyyy, mm-dd-yyyy
function isDate(str){
	var re = /^(\d{1,2})[\s\.\/-](\d{1,2})[\s\.\/-](\d{4})$/;
	if (!re.test(str)) return false;
	var result = str.match(re);
	var m = parseInt(result[1]);
	var d = parseInt(result[2]);
	var y = parseInt(result[3]);
	if (m < 1 || m > 12 || y < 1900 || y > 2100) return false;
	if (m == 2) {
		var days = ((y % 4) == 0) ? 29 : 28;
 	} else if (m == 4 || m == 6 || m == 9 || m == 11) {
		var days = 30;
	} else {
		var days = 31;
	}
	return (d >= 1 && d <= days);
} // isDate