javascript - 簡単なJavaScriptの修正（日付/時刻）

Question

このコードのどこが間違っているのですか？

var now = Date.now();
var HoursLater = now.addHours(6);
Date.prototype.addHours= function(h){
    this.setHours(this.getHours()+h);
    return this;
}

document.write(HoursLater);

</ p>

Answer 1

車輪の再発明をする必要はありません！

周りにあなたに多くの時間を節約する良いライブラリがあります。

date.jsを見てください。すでにaddHours（）があります！

.addHours ( Number hours ) : Date

Adds the specified number of hours to this instance given the number of hours to add. The number can be positive or negative.

// Solution to your problem with date.js ;)
Date.today().addHours(6);

// What date is next thursday?
Date.today().next().thursday();

// Add 3 days to Today
Date.today().add(3).days();

Answer 2

Your prototype method addHours is defined on the Date() object, not on Date.now().

Just modify your first line to var Now = new Date();

Also move the prototype method definition for addHours to the top(due to the order of execution of the previous 2 statements).

http://jsfiddle.net/ATUpF/