codeigniter dropdown selected issue [closed]

<?php
    $options = array();
    $options[0] = "Kies het kampioenschap";
    foreach ($kampioenschappen as $kampioenschap) {
        $options[$kampioenschap->kampioenschapsId] = $kampioenschap->naam;
    }
    $js = 'id="kampioenschap" style="width: 600px';
    echo form_dropdown('kampioenschap', $options, '0', $js) . "\n";
?>

I want to create a dropdown form so the user can select a championship that he wants to view.

This all works but I have a problem with showing the first value in the $options array. In the CodeIgniter docs they say:

echo form_dropdown('name', $options, 'selectedvalue', $js);

If I look at the source output in my browser, this is what I see:

    <select name="kampioenschap" id="kampioenschap" style="width: 600px>
    <option value="0" selected="selected">Kies het kampioenschap</option>
    <option value="2">Nationaal kampioenschap</option>
    <option value="3">Waals kampioenschap</option>
    <option value="5">Vlaams kampioenschap</option>
    </select>

For me this looks like valid xhtml code. But when I open the page with Firebug or DragonFly, I get this:

<select id="kampioenschap" 
selected="selected" 0"="" style="width:    600px> 

This makes no sense to me, I have other dropdown in my application that work just fine.

Can someone point out the mistake I made?