Php include not working in firefox

all my include code not working if firefox
like this

<?php include(“nav.inc.php”); ?>

works well in IE.

how do i fix this?

Php code runs on server side. Browsers are client side. You can go view source in any browser to see if nav.inc.php is outputting something.

Chances are if you are outputting some javascript with nav.inc.php then that javascript is not firefox compatible. Try using the error console in firefox to look out for js errors.