first glance at the webpage i thought itd be a javascript, but when i looked at page's source code, i couldn't find the line, so i went to the next place and found a javascript that would show the viewer's ip address:

Code:
<!-- ONE STEP TO INSTALL IP ADDRESS:

  1.  Copy the coding into the HEAD of your HTML document  -->

<!-- STEP ONE: Paste this code into the HEAD of your HTML document  -->

<HEAD>

<SCRIPT LANGUAGE="JavaScript">

<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->

<!-- Begin
// http://www.kdcgrohl.com

// Depending on your server set-up,
// you may need to use the ".shtml"
// extension [instead of the "html"
// or "htm"] as the script uses Server
// Side Includes. To display in the
// title bar, exclude the
//"<title></title>" code from the page.

// This part gets the IP
var ip = '<!--#echo var="REMOTE_ADDR"-->';

// This part is for an alert box
alert("Your IP address is "+ip);

// This part is for the status bar
window.defaultStatus = "Your IP address is "+ip;

// This part is for the title bar
document.write("<title>Your IP address is "+ip+"</title>");
//  End -->
</script>


<p><center>
<font face="arial, helvetica" size"-2">Free JavaScripts provided<br>
by <a href="http://javascriptsource.com">The JavaScript Source</a></font>
</center><p>

<!-- Script Size:  1.09 KB -->
from: http://javascript.internet.com/user-...p-address.html