MutationObserver = window.MutationObserver || window.WebKitMutationObserver;

var observer = new MutationObserver(function(mutations, observer) {

    // fired when a mutation occurs

    console.log(mutations);

    // ...

});

// define what element should be observed by the observer

// and what types of mutations trigger the callback

observer.observe(document, {

    subtree: true,

    attributes: true,

    childList: true,

    characterData: true,

    attributeOldValue: true,

    characterDataOldValue: true

});