AJAX update content every X seconds

I was asked several times on Twitter how to update some web page section or a block content on a page every x seconds. Some real life examples of this functionality are Twitter search results that come out when there are new tweets with search keyword or bit.ly real time link tracking that updates it’s charts every 5 seconds.

It is clear without saying that we are going to update our page content using AJAX and of course we love AJAX in jQuery flavor. So key to this functionality is JavaScript's built-in setInterval() function. It lets you to run some javascript function every X seconds. For example, the following code would pop alert box every five seconds:

setInterval( "alert('Hello')", 5000 );

Now consider we want to update shouts in our shoutbox every 10 seconds.

function updateShouts(){
    // Assuming we have #shoutbox
    $('#shoutbox').load('latestShouts.php');
}
setInterval( "updateShouts()", 10000 );

The code above will run every 10 seconds (10,000 ms) and update the contents of #shotbox with new shouts.