Reading cookie expiration date

Question

Is it possible to read cookie expiration date using JavaScript?

If yes, how? If not, is there a source I can look at?

Answer 1

If you have control over the code where the cookie is set, then you can add code to store the expiration date in the browser's local storage for later retrival. For example:

// set cookie with key and value to expire 30 days from now
var expires = new Date(Date.now() + 30 * 24 * 60 * 60 * 1000);
document.cookie = [
    "key=value",
    "expires=" + expires.toUTCString()
].join("; ");

// store cookie expiration date for key in local storage
if (window.localStorage) {
    localStorage.setItem("keyExpires", expires.toISOString());
}

Later, you can lookup when the cookie expires in local storage. For example:

var expires = localStorage.getItem("keyExpires");

Local storage currently has broad support.

https://caniuse.com/#feat=namevalue-storage