What is the best way to initialize a JavaScript Date to midnight?

What is the simplest way to obtain an instance of new Date() but set the time at midnight?

The setHours method can take optional minutes, seconds and ms arguments, for example:

var d = new Date();
d.setHours(0,0,0,0);

That will set the time to 00:00:00.000 of your current timezone, if you want to work in UTC time, you can use the setUTCHours method.