mutation-observer.js

var observer = new MutationObserver(function(mutations) {
    //console.log('OBSERVED', mutations);
    var observation = parseInt(Math.random() * 100);
    console.group('Observation ' + observation);
    mutations.forEach(function(mutation) {
        console.log('%s: %s', mutation.target.nodeName, mutation.type, mutation);
    });    
    console.groupEnd();
});
var config = {childList: true, attributes: true, characterData: true, subtree: true, attributeOldValue: true, characterDataOldValue: true};

observer.observe($0, config);