Need help with cookies

I have this code to set cookies and when they expire, but I would like to know what do the numbers mean. So, that I may increase it. Additionally, Can I put a name to a cookie that way if I have a new message to show it won’t be blocked?
if (document.cookie.indexOf(‘visited=true’) == -1) {
var oneDay = 1000 * 60 * 60 * 24 * 1;
var expires = new Date((new Date()).valueOf() + oneDay);
document.cookie = “visited=true;expires=” + expires.toUTCString();

If the indexOf ‘visited=true’ is -1, that means that ‘visited=true’ is not in the string of document.cookie. So the conditional is “if ‘visited=true’ is not found”.

var oneDay is calculating the number of milliseconds in a 24 hour period.

var expires is creating a date object of 24 hours from the present.

Then the value “visited=true” is being set to the cookie and set to expire 24 hours from the present.

If you want to inrease the expire date, set the variable “expires” to the number of milliseconds equal to how far in advance you want the cookie to expire.

Thank you WolfShade! That helped a lot!