ADD DATE AND TIME TO YOUR WEB PAGES

If your Web site has an international audience, you may want to use UTC for dates.

Important methods for international time include:

toLocaleString();

//returns date and time as a string based on local time

toUTCString();

//returns date and time as a string based on UTC time, as shown in the previous section

getTimezoneoffset();

//gives difference in minutes between local time and UTC time

For example, this code:

var now = new Date();
document.write (now.toLocaleString() + "<br>");
document.write(now.toUTCString() + "<br>");
document.write(now.getTimezoneOffset() + "<br>");

returns this output to the page:

Sunday, September 14, 2003 3:22:17 AM
Sun, 14 Sep 2003 09:22:17 UTC
360

You can use getTimezoneOffset() to determine the hours ahead or behind of UTC, for example:

var myTime = new Date ();
var zone = myTime.getTimezoneOffset();
zone = zone / 60;
if (zone < 0) {
var factor = "later";
}
else 
factor = "earlier";
document.write (myTime + " is " +  zone + 
" hours " + factor + " than UTC Time.");

returns this output to the page:

Sun Sep 14 03:42:47 MDT 2003 is 
6 hours earlier than UTC Time.

JavaScript includes methods for UTC time that are equivalent to the methods mentioned earlier in this lesson, such as:

setUTCDate();
setUTCFullYear();
getUTCDate();
getUTCFullYear();

and so on.