How can I set a cookie with expire time?

I am setting a cookie with JavaScript and it is working fine but it is not taking the expire time I am giving. It keeps on taking session value regardless of what I give, below is the code which I took from here

var now = new Date();
var time = now.getTime();
var expireTime = time + 1000*60;
now.setTime(expireTime);
var tempExp = 'Wed, 31 Oct 2012 08:50:17 GMT';
document.cookie = aaa+'='+sStr+';expires='+now.toGMTString()+';path=/';

I tried giving hard-coded value but still it is showing expire as session in chrome dev tool

var tempExp = 'Wed, 31 Oct 2012 08:50:17 GMT';
document.cookie = aaa+'='+sStr+';expires='+tempExp+';path=/';

Any idea what I am doing wrong?

I've set the time to 1000*36000.

function display() { 
  var now = new Date();
  var time = now.getTime();
  var expireTime = time + 1000*36000;
  now.setTime(expireTime);
  document.cookie = 'cookie=ok;expires='+now.toUTCString()+';path=/';
  //console.log(document.cookie);  // 'Wed, 31 Oct 2012 08:50:17 UTC'
}

Below are code snippets to create and delete a cookie. The cookie is set for 1 day.

// 1 Day = 24 Hrs = 24*60*60 = 86400.

1. By using max-age:

   • Creating the cookie:

   document.cookie = "cookieName=cookieValue; max-age=86400; path=/;";
   

   • Deleting the cookie:

   document.cookie = "cookieName=; max-age=- (any digit); path=/;";
   

2. By using expires:

   • Syntax for creating the cookie for one day:

   var expires = (new Date(Date.now()+ 86400*1000)).toUTCString();
   document.cookie = "cookieName=cookieValue; expires=" + expires + ";path=/;"
   

Here's a function I wrote another application. Feel free to reuse:

function writeCookie (key, value, days) {
	var date = new Date();

	// Default at 365 days.
	days = days || 365;

	// Get unix milliseconds at current time plus number of days
	date.setTime(+ date + (days * 86400000)); //24 * 60 * 60 * 1000

	window.document.cookie = key + "=" + value + "; expires=" + date.toGMTString() + "; path=/";

	return value;
};

document.cookie = "cookie_name=cookie_value; max-age=31536000; path=/";

Will set the value for a year.

Use like this (source):

function setCookie(c_name,value,exdays)
{
	
var exdate=new Date();
exdate.setDate(exdate.getDate() + exdays);
var c_value=escape(value) + ((exdays==null) ? "" : "; expires="+exdate.toUTCString());
document.cookie = c_name+"="+c_value+"; path=/";
}

I'd like to second Polin's answer and just add one thing in case you are still stuck. This code certainly does work to set a specific cookie expiration time. One issue you may be having is that if you are using Chrome and accessing your page via "http://localhost..." or "file://", Chrome will not store cookies. The easy fix for this is to use a simple http server (like node's http-server if you haven't already) and navigate to your page explicitly as "http://127.0.0.1" in which case Chrome WILL store cookies for local development. This had me hung up for a bit as, if you don't do this, your expires key will simply have the value of "session" when you investigate it in the console or in Dev Tools.

I use a function to store cookies with a custom expire time in days:

// use it like: writeCookie("mycookie", "1", 30)
// this will set a cookie for 30 days since now
function writeCookie(name,value,days) {
  if (days) {
    var date = new Date();
    date.setTime(date.getTime()+(days*24*60*60*1000));
    var expires = "; expires="+date.toGMTString();
  }
  else var expires = "";
  document.cookie = name+"="+value+expires+"; path=/";
}

Your browser may be configured to accept only session cookies; if this is your case, any expiry time is transformed into session by your browser, you can change this setting of your browser or try another browser without such a configuration