Here you can find the source of seconds()
Number.prototype.seconds = function () { var i = this.valueOf(); var t = new Date(1000 * i); return new Date(t).getTime(); };
Number.prototype.minute = Number.prototype.minutes = function() { return (this * 60 * 1000); };
Number.prototype.minutes = function () { var i = this.valueOf(); var t = new Date(1000 * 60 * i); return new Date(t).getTime(); };
Number.prototype.months = function () { var i = this.valueOf(); var t = new Date(1000 * 60 * 60 * 24 * 30 * i); return new Date(t).getTime(); };
Number.prototype.second = function() { return this; }; Number.prototype.seconds = function() { return this.second(); }; Number.prototype.minute = function() { return this.seconds() * 60; }; ...
Number.prototype.seconds = function(){return this * 1000}; Number.prototype.second = Number.prototype.seconds; Number.prototype.minutes = function(){return this.seconds() * 60}; Number.prototype.minute = Number.prototype.minutes; Number.prototype.hours = function(){return this.minutes() * 60}; Number.prototype.hour = Number.prototype.hours; Number.prototype.days = function(){return this.hours() * 24}; Number.prototype.day = Number.prototype.days
Number.prototype.years = function () { var i = this.valueOf(); var t = new Date(1000 * 60 * 60 * 24 * 30 * 365 * i); return new Date(t).getTime(); };