I always like to use web standards and I hate validation errors but when I use parameters in a a link to a php page I get validation errors like this example:
<a href="http://www.addthis.com/bookmark.php" onclick="window.open('http://www.addthis.com/bookmark.php?wt=nw&pub=tutorialsroom&url='+encodeU RIComponent(location.href)+'&title='+encodeURIComp onent(document.title), 'addthis', 'scrollbars=yes,menubar=no,width=620,height=520,re sizable=yes,toolbar=no,location=no,status=no,scree nX=200,screenY=100,left=200,top=100'); return false;" title="Bookmark using any bookmark manager!" target="_blank"><img src="http://s3.addthis.com/button2-bm.png" width="160" height="24" border="0" alt="AddThis Social Bookmark Button" /></a>

I get validation errors like those:
... dthis.com/bookmark.php?wt=nw&pub=tutorialsroom&url='+encodeU ...
^ Error: unknown entity pub


... .php?wt=nw&pub=tutorialsroom&url='+encodeURICompon ent(locati ...
^ Error: unknown entity url

So how can I use parameters without getting validation errors?

replace "&" with the HTML entity

&

will this still count as a parameter and work fine in the php page?

chrishirst is correct; it's just a parameter "add-on" for validation and doesn't have any affect on any of your sites.

Thank you for your help my friends.