Hi all, I am pulling some info from a database with the following code:

<input type="button" value="Export to Excel" onClick="window.navigate('breakfast_service.php?action=export')">

Here is the code for that action.

<?php  

 if ($_GET['action'] == 'export')
    {

        // Get the registration data
        $user = 'root';
        $pass = 'billiards';
        $server = 'localhost';

        $link = mysql_connect($server, $user, $pass);
        if (!$link)
        {
            die('Could not connect to database!' . mysql_error());
        }

        mysql_select_db('breakfast', $link);

        $query = "SELECT * FROM registration";
        $result = mysql_query($query);
        mysql_close($link);


        // format into CSV
        $contents = "id, school_id, first_name, last_name, email, attending, created_on\n";
        $num = mysql_num_rows($result);
        for ($i = 0; $i < $num; $i++)
        {
            $row = mysql_fetch_array($result);
            $id = $row['id'];
            $school_id = $row['school_id'];
            $fname = $row['first_name'];
            $lname = $row['last_name'];
            $email = $row['email'];
            $attending = ($row['attending'] == 0) ? 'No' : 'Yes';
            $date = $row['created_on'];

            $contents = $contents . "$id, $school_id, $fname, $lname, $email, $attending, $date\n";
        }

        // return as excel file
        $filename = "export.csv";
        header('Content-type: application/ms-excel');
        header('Content-Disposition: attachment; filename='.$filename);
        echo $contents;
    }
    ?>

This combination of code works excellent in IE, but fails to do create/download a file in Firefox or Chrome. Why?