<script language="php"> works as a render code block.

<script language="php" runat="server"> and
<script runat="server" language="php"> should also be made to work. I think the way that you are searching for them is incorrect. It is like php is specifically looking for
<script language="php"> although white-space (between script and language) is ignored.  I would say make the runat="server" mandatory, but since you probably won't do that at least have PHP igonre the runat attribute or all attributes that are not 'language'.

What happens if someone writes a browser that supports some kind of php on the client? I know. Not likely.  But think ahead.

Thanks,

Kelly