<form action="<?php bloginfo('url'); ?>" method="get">

<?php
$taxonomies = array('subjects');
$args = array('orderby'=>'name','hide_empty'=>true);
$select = get_terms_dropdown($taxonomies, $args);
 
$select = preg_replace("#<select([^>]*)>#", "<select$1 onchange='return this.form.submit()'>", $select);
echo $select;
?>
    <noscript><div><input type="submit" value="Go" /></div></noscript>
    </form>

<form action="
Fatal error: Call to undefined function bloginfo() on line 1