If statement returns wrong value [PHP]

I have weird problem. I need to select option in input select. This is my code:

<?php
$val = 'box=Box|billboard=Billboard|insert=Insert|skyscrapper=Skyscrapper';
foreach ($val as $val) {
    $val=explode("=", $val);
    if ($selected==$val[0]) {
        echo '<option value="',stripslashes($val[0]),'" selected="selected">',stripslashes($val[1]),'</option>';
    } else {
        echo '<option value="',stripslashes($val[0]),'">',stripslashes($val[1]),'</option>';
    }
}
?>

This script select me all of options - every option has selected="selected". Even when I print values it is like if (0==box) which should returns false but it returns true. What is going on?