js>t1 = new Date()
Thu Jan 29 2009 14:19:28 GMT-0500 (Eastern Standard Time)
js>t2 = new Date()
Thu Jan 29 2009 14:19:31 GMT-0500 (Eastern Standard Time)
js>t2-t1
2672
js>t3 = new Date('2009 Jan 1')
Thu Jan 01 2009 00:00:00 GMT-0500 (Eastern Standard Time)
js>t1-t3
2470768442
js>t1>t3
true
var date = new Date(); // will give you todays date.
// following calls, will let you set new dates.
setDate()
setFullYear()
setHours()
setMilliseconds()
setMinutes()
setMonth()
setSeconds()
setTime()
var yesterday = new Date();
yesterday.setDate(...date info here);
if(date>yesterday) // will compare dates
Dateオブジェクト](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date)は、各日付ごとに1つずつ作成し、
>、`フォーマットは？
JavascriptでDateオブジェクトを作成すれば、ミリ秒の差を得るためにそれらを差し引くことができます（編集：あるいは単に比較することもできます）。