Man.wakeUp() with and without apply

Without apply With apply
function Man() { } Man.prototype = { valet : false, wakeUp : function(event) { alert(this.valet + "? Some breakfast, please."); } }; var wooster = new Man(); wooster.valet = "Jeeves"; window.onload = function() { var button1 = document.getElementById("morning1"); var button2 = document.getElementById("morning2"); button1.addEventListener( "click", wooster.wakeUp, false ); button2.addEventListener( "click", function() { wooster.wakeUp.apply(wooster, arguments); }, false ); }