document.cookie
Cookies are small pieces of data stored in the browser. Access them via document.cookie as a semicolon-separated string.
document.cookie = "username=Alice";
document.cookie = "theme=dark";
console.log(document.cookie);Setting Cookies with Options
Set path, expiration, and Secure/HttpOnly flags. Use max-age or expires for persistence.
function setCookie(name, value, days) {
const date = new Date();
date.setTime(date.getTime() + days * 86400000);
document.cookie = name + "=" + value + ";expires=" + date.toUTCString() + ";path=/";
}
setCookie("preferences", "dark_mode", 7);
console.log(document.cookie);Reading & Deleting Cookies
Parse document.cookie to read specific values. Delete by setting a past expiration date.
function getCookie(name) {
const cookies = document.cookie.split("; ");
for (let c of cookies) {
const [key, value] = c.split("=");
if (key === name) return value;
}
return null;
}
function deleteCookie(name) {
document.cookie = name + "=;expires=Thu, 01 Jan 1970 00:00:00 UTC;path=/";
}
console.log(getCookie("username"));
deleteCookie("username");
console.log(getCookie("username"));