var Proxy = function(){};

var p =   Proxy.create(this, {

    get: function(proxy, name) { // intercepts property access

      return 'Hello, '+ name;

    },

    set: function(proxy, name, value) { // intercepts property assignments

      console.debug(name +'='+ value);

      return true;

    }

  });

​

alert('foo');

p.fooppp = 'bar';

p.bar = 'ba';