Yesterday a had to create a script where some cells in a html table would change their values based on changed values on the server.
So, all it took is to set the timer and at given period of times to call a server side script and gather the info and then display it in right places.
Below is a simplified version of this script. It will call a server script each secod and display the value in a DIV.
The first script is the one that you will load in the browser:
Current Time is: <div align="center" id="clockID"></div><script src="js/jquery.js"></script><script language="JavaScript">
var refreshId = setInterval(function()
$('#clockID').load('clock.cfm?rnd='+ Math.random());
}, 1000);

And the server-side script is:
<cfoutput>#TimeFormat(Now(), "HH:mm:ss")#</cfoutput>