Before switching to XHTML I used the following script to enable website viewers to have two windows open and toggle between them:
<script type="text/javascript"> 
var newWindow = null; 
function makeNewWindow(href, preview) 
    if (newWindow && !newWindow.closed) 
        newWindow = open(href, preview); 
    return false; 
HTML Code:
<h3>When you click <a href="/home/<?php echo $site_address;?>" target="preview" onclick="return makeNewWindow(this.href,">here</a> you will open a new tab where you will see....</h3>
Now target="preview" does not validate for XHTML. It brings up the error message: 'there is no attribute "target"'. Suggestions?