Functions for setting, getting and deleting cookies via JavaScript

cookies.js

/**
 * Set a cookie
 *
 * @param {string} cookieName
 * @param {string} cookieValue
 * @param {object} cookieOptions (expires, domain, path)
 */
function setCookie(cookieName, cookieValue, cookieOptions) {
    cookieOptions = cookieOptions || {};
    if (cookieValue) {
        if (cookieOptions.expires) {
            var d = new Date();
            d.setTime(d.getDate() + cookieOptions.expires);
            cookieValue += '; expires=' + d.toUTCString();
        }
        if (cookieOptions.domain) {
            cookieValue += "; domain=" + cookieOptions.domain;
        }
        if (cookieOptions.path) {
            cookieValue += "; path=" + cookieOptions.path;
        }
        document.cookie = cookieName + '=' + cookieValue;
    }
}

/**
 * Get the value for a specific cookie
 *
 * @param {string} cookieName
 * @param {string|null} defaultValue
 * @returns {string}
 */
function getCookie(cookieName, defaultValue) {
    if (typeof defaultValue === 'undefined') {
        defaultValue = null;
    }
    cookieName += "=";
    var cookieCollection = document.cookie.split(';');
    for (var i = 0; i < cookieCollection.length; i++) {
        var c = cookieCollection[i].trim();
        if (c.indexOf(cookieName) === 0) {
            return c.substring(cookieName.length, c.length);
        }
    }
    return defaultValue;
}

/**
 * Delete a cookie
 *
 * @param cookieName
 */
function deleteCookie(cookieName) {
    var value = getCookie(cookieName);
    setCookie(cookieName, value, -1);
}