can i be notified of cookie changes in client side javascript

Question

Can I somehow follow changes to cookies (for my domain) in my client side javascript. For example a function that gets called if a cookie gets changed , deleted or added

In order of preference

• standard cross browser
• cross browser
• browser specific
• extension / plugin

Why? because cookies I depend on in window / tab #1 can get changed in window / tab #2.

I found out that chrome allows extensions to be notified of cookies changes. But thats my least favorite option

Answer 1

One option is to write a function that periodically checks the cookie for changes:

var checkCookie = function() {

    var lastCookie = document.cookie; // 'static' memory between function calls

    return function() {

        var currentCookie = document.cookie;

        if (currentCookie != lastCookie) {

            // something useful like parse cookie, run a callback fn, etc.

            lastCookie = currentCookie; // store latest cookie

        }
    };
}();

window.setInterval(checkCookie, 100); // run every 100 ms

• This example uses a closure for persistent memory. The outer function is executed immediately, returning the inner function, and creating a private scope.
• window.setInterval