Javascript return number of days,hours,minutes,seconds between two dates

Here's in javascript: (For example, the future date is New Year's Day)

DEMO (updates every second)

var dateFuture = new Date(new Date().getFullYear() +1, 0, 1);
var dateNow = new Date();

var seconds = Math.floor((dateFuture - (dateNow))/1000);
var minutes = Math.floor(seconds/60);
var hours = Math.floor(minutes/60);
var days = Math.floor(hours/24);

hours = hours-(days*24);
minutes = minutes-(days*24*60)-(hours*60);
seconds = seconds-(days*24*60*60)-(hours*60*60)-(minutes*60);

Just figure out the difference in seconds (don't forget JS timestamps are actually measured in milliseconds) and decompose that value:

// get total seconds between the times
var delta = Math.abs(date_future - date_now) / 1000;

// calculate (and subtract) whole days
var days = Math.floor(delta / 86400);
delta -= days * 86400;

// calculate (and subtract) whole hours
var hours = Math.floor(delta / 3600) % 24;
delta -= hours * 3600;

// calculate (and subtract) whole minutes
var minutes = Math.floor(delta / 60) % 60;
delta -= minutes * 60;

// what's left is seconds
var seconds = delta % 60;  // in theory the modulus is not required

EDIT code adjusted because I just realised that the original code returned the total number of hours, etc, not the number of hours left after counting whole days.