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Cover image for Vanilla JavaScript Cookies 🍪

Vanilla JavaScript Cookies 🍪

dailydevtips1 profile image Daily Dev Tips Originally published at daily-dev-tips.com ・2 min read

Today we'll be looking into working with Cookies in JavaScript.
It's not the most widely used function, but great to keep track of small things like whether someone clicked a cookie bar.

We can set, get, change and, delete a cookie.

JavaScript Set Cookie

To set a cookie in JavaScript, we use the document.cookie property.

First we must understand cookies are set as a key, value pair

key = value

So to set a cookie:

document.cookie = 'username=Chris';

We can even set a expire date:

document.cookie = 'username=Chris; expires=Sun, 01 Jan 2023 12:00:00 UTC';

JavaScript Read Cookie

To read a cookie we can use the following:

var username = document.cookie;
username = Chris;
second = bla;

This will return the full cookie object, so we need to split it ourself like so:

var username = getCookie('username');
console.log(username);
// Chris

function getCookie(name) {
  // Add the = sign
  name = name + '=';

  // Get the decoded cookie
  var decodedCookie = decodeURIComponent(document.cookie);

  // Get all cookies, split on ; sign
  var cookies = decodedCookie.split(';');

  // Loop over the cookies
  for (var i = 0; i < cookies.length; i++) {
    // Define the single cookie, and remove whitespace
    var cookie = cookies[i].trim();

    // If this cookie has the name of what we are searching
    if (cookie.indexOf(name) == 0) {
      // Return everything after the cookies name
      return cookie.substring(name.length, cookie.length);
    }
  }
}

JavaScript Changing a Cookie

Sometimes we want to update a cookie; this is the same as the creation:

document.cookie = 'username=Nicole; expires=Sun, 01 Jan 2023 12:00:00 UTC';

JavaScript Deleting a Cookie

To delete a specific cookie, we have to set its date to be passed:

document.cookie = 'username=; expires=Thu, 01 Jan 1970 00:00:00 UTC;';

View the demo to test with on Codepen.

See the Pen JavaScript Cookies by Chris Bongers (@rebelchris) on CodePen.

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Daily Dev Tips

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