mixing php variable with javascripts onchange event

[lukeurtnowski]

Im trying to use a javascript event (OnChange) to parse a php variable to another page, is it something like this?

<select name="SID1" style="visibility: hidden" onchange="document.location.href='Category.php?CatID=".$result['CatID']."'>

Any help is greatly appreciated.

[Weedpacket]

<select name="SID1" style="visibility: hidden" onchange="document.location.href='Category.php?CatID=<?php echo $result['CatID']?>'>