Is it possible to work out HTML5 utilisation of session/local storage?

Question

Is it possible to work out utilisation of session storage?

Ideally to return current size of site session storage contents

http://www.w3schools.com/html/html5_webstorage.asp

Answer 1

I used this and it matched the local storage size here.

function getLocalStorageSize() {
    var key, item, bytes = 0, keys = Object.keys(localStorage);

    for (var i = 0; i < keys.length; i++) {
        key = keys[i];
        item = localStorage[key];
        bytes += key.length + item.length;
    }

    return bytes;
}