validation for email, ip and netmask

function valid_email(email) {return (email != "" && email.length <= 256 && /^([\w\-.+_]{1,64}@([\w-]{1,255}\.)+[\w-]{2,4})?$/.test(email));}

function valid_ip(text) {return ( /^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/.test(text) );}

function valid_netmask(mask) {    var correct_range = {'128': 1, '192': 1, '224': 1, '240': 1, '248': 1, '252': 1, '254': 1, '255': 1, '0':1};    var m = mask.split('.');    for (var i = 0; i <= 3; i ++) {        if (!(m[i] in correct_range)) {            return false;        }    }    if ((m[0] != 255 && m[1] != 0) || (m[1] != 255 && m[2] != 0) || (m[2] != 255 && m[3] != 0)) {        return false;    }    return true;}