Validate IPv4

function ip2long(str) { if (IPv4_REGEX.test(str)) { var result = 0; var parts = str.split('.'); for (var i = 0; i < 4; ++i) { result += parts[i] * Math.pow(256, 3 - i); } return result; } return null; }

IPv4_REGEX = /^(1?[1-9]?\d|2[0-4]\d|25[0-5])(\.(1?[1-9]?\d|2[0-4]\d|25[0-5])){3}$/;