Here you can find the source of addHour()
Date.prototype.addHour = function(){
this.setTime(this.getTime() + (60 * 60 * 1000));
};
Date.prototype.addHalfHour = function() {
this.setTime(this.getTime() + 30 * 60 * 1000);
};
Date.prototype.addHours= function(h){ this.setHours(this.getHours()+h); return this;
Date.prototype.addHours = function(h) { this.setHours(this.getHours() + h); return this; Date.prototype.addSeconds = function(s) { this.setSeconds(this.getSeconds() + s); return this;
Date.prototype.addHours = function(h) { this.setTime(this.getTime() + (h*60*60*1000)); return this;
Date.prototype.addHours= function(h){ this.setHours(this.getHours()+h); return this; var d = new Date(); console.log(d.addHours(24));