plainJS

Functions / Utilities

Set cookie, get cookie and delete cookie

2015 page

This is the original page from 2015, kept at its address while the tested rewrite is in progress. The code is of its time: it ran in Internet Explorer and does not use what browsers have gained since. The rewrite replaces it here.

In short

Size optimized functions for creating, reading and erasing cookies in JavaScript.

Use the following three functions for working with cookies.

js
function getCookie(name) {
    var v = document.cookie.match('(^|;) ?' + name + '=([^;]*)(;|$)');
    return v ? v[2] : null;
}
js
function setCookie(name, value, days) {
    var d = new Date;
    d.setTime(d.getTime() + 24*60*60*1000*days);
    document.cookie = name + "=" + value + ";path=/;expires=" + d.toGMTString();
}
js
function deleteCookie(name) { setCookie(name, '', -1); }

All three functions are optimized on size. You may squeeze out some more bytes by minification.

Warning: According to HTTP Cookie specs, semi-colons, commas, equals signs, and white spaces are not allowed characters. If you do need to use them, you will need to write a custom encode and decode function. encodeURIComponent() and decodeURIComponent() may be useful here.