Window.location / new window?

Hello,

I have a php page where a list of items comes from a data base. Each item locates in a cell and onclick, related page loads (list.php). The problem is this page does not open in a new window. How should I modify the code? I tried replacing window.location with window.open command but it wont work.

echo “<td width=230 style=“vertical-align:top” class=boxInactive onclick=“window.location='list.php?Id=” . $data[$i + ($j * $rows)] .”’;return false;" ";

please help
thanks