remove the body onload statement and associated code
change the HTML to
<div class=button-new>Themes:
<button class=white type=submit onclick="CSS('tw',1);">.
</button>
<button class=khaki type=submit onclick="CSS('tk',1);">.
</button>
<button class=black type=submit onclick="CSS('tb',1);">.
</button>
</div>
insert this code just before the </BODY> tag
<script type="text/javascript">
/*<![CDATA[*/
function CSS(c,d){
if (c){
document.body.className=c;
document.cookie='css='+c+(typeof(d)=='number'?';expires='+(new Date(new Date().getTime()+d*86400000).toGMTString())+';path/;':';');
}
}
function cookie(nme){
var re=new RegExp(nme+'=[^;]+','i');
return document.cookie.match(re)?document.cookie.match(re)[0].split("=")[1]:null;
}
CSS(cookie('css'),1);
/*]]>*/
</script>
function CSS parameters are:
the first function parameter is the class name,
the second parameter(in red) refers to the number od days to restor the CSS else it is the browser session