PHP Code:
$controls="<a href=\"$PHP_SELF?action=toplist&topnumber=$topnumber\">Show $topnumber sites</a> - Max: <select name=\"topnumber\" onchange=\"window.location=('toplist.php?s=$session[sessionhash]&topnumber=' + this.options[this.selectedIndex].value + '&action=toplist')\">";
$controls.="<option";
if ($topnumber=="10") $controls.= " selected";
$controls.=">10</option>";
$controls.="<option";
if ($topnumber=="25") $controls.= " selected";
$controls.=">25</option>";
$controls.="<option";
if ($topnumber=="50") $controls.= " selected";
$controls.=">50</option>";
$controls.="<option";
if ($topnumber=="75") $controls.= " selected";
$controls.=">75</option>";
$controls.="<option";
if ($topnumber=="100") $controls.= " selected";
$controls.=">100</option>";
$controls.="<option";
if ($topnumber=="all") $controls.= " selected";
$controls.=">all</option></select>";
the first line was missing some slashes and an ending semicolon.