I am using the following script so a viewer can toggle back and forth between two windows. It opens a new window OK, but does not bring the window to the front once it is opened and the viewer hits the link again. How do I do this?

var newWindow = null; 
function makeNewWindow(href, preview) 
    if (newWindow && !newWindow.closed) 
        newWindow = open(href, preview); 
    return false; 
HTML Code:
<a href="/home/<?php echo $site_address;?>" onclick="return makeNewWindow(this.href, 'preview')">View now</a>