function Person() {
}
Person.prototype.sayHello = function() {
 console.log('Hello, Alice!');
};
function Decorator(param) {
 this.person = param;
}
Decorator.prototype.sayHello = function() {
 this.person.sayHello();
 console.log('Hello, Bruce!');
};
Decorator.prototype.sayGoodbye = function() {
 console.log('Bye, everyone!');
};
new Decorator(new Person()).sayHello();
/*

var div = document.getElementById('div');
div.onclick = function() {
 console.log('First click!');
}
var decorator = function() {
 var args = arguments;
 var element = document.getElementById(args[0]);
 if (typeof element.onclick === 'function') {
 var firstClick = element.onclick;
 element.onclick = function() {
 firstClick();
 args[1]();
 }
 }
 else
 element.onclick = args[1];
}
decorator('div', function() {
 console.log('Second click!');
});
/*