Object Observe advanced

HTML

<button id="add">Add property</button>
<button id="update">Update property</button>

JavaScript

/*
Object.observe() demo.
Chrome Beta (36) required (as of 9th June 2014.
Results are logged to the console.
*/

var btnAdd = document.getElementById('add'),
    btnUpd = document.getElementById('update');

var myObj = {
    some: 'thing'
}

Object.observe(document.cookie, function (changes) {
    changes.forEach( function (change) {
        console.log(change);
    });
});

function disable (elTarget) {
    elTarget.setAttribute('disabled',true);
}

btnAdd.addEventListener('click', function (ev) {
    disable(btnAdd);
    myObj.different = 'thing';
});

btnUpd.addEventListener('click', function (ev) {
    disable(btnUpd);
    myObj.some = 'one';
});