Round a Date() to the nearest 5 minutes in javascript

Question

Using a Date() instance, how might I round a time to the nearest five minutes?

For example: if it's 4:47 p.m. it'll set the time to 4:45 p.m.

Answer 1

That's pretty simple if you already have a Date object:

var coeff = 1000 * 60 * 5;
var date = new Date();  //or use any other date
var rounded = new Date(Math.round(date.getTime() / coeff) * coeff)