wp_dropdown_categories – remove  

You could use the echo parameter to return the output into a variable:

$html =  wp_dropdown_categories( array( 'echo' => 0 ) );

and then replace  :

echo str_replace( ' ', '', $html );

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)