function my_Clock() { this.cur_date = new Date(); this.hours = this.cur_date.getHours(); this.minutes = this.cur_date.getMinutes(); this.seconds = this.cur_date.getSeconds(); } my_Clock.prototype.run = function () { setInterval(this.update.bind(this), 1000); }; my_Clock.prototype.update = function () { this.updateTime(1); console.log(this.hours + ":" + this.minutes + ":" + this.seconds); }; my_Clock.prototype.updateTime = function (secs) { this.seconds+= secs; if (this.seconds >= 60) { this.minutes++; this.seconds= 0; } if (this.minutes >= 60) { this.hours++; this.minutes=0; } if (this.hours >= 24) { this.hours = 0; } }; var clock = new my_Clock(); clock.run();