WordPress Gems 1 - selected, checked & disabled

/*
Installation paths and URLs, with SSL support: http://codex.wordpress.org/Determining_Plugin_and_Content_Directories
*/

/* standard solution to populate a selection drop-down */
<?php $sel = ' selected="selected"'; ?>
<label for="<?= $this->get_field_id('sortby'); ?>"><?php _e('Sort by:', 'wpdtree'); ?></label>
<select id="<?= $this->get_field_id('sortby'); ?>" name="<?= $this->get_field_name('sortby'); ?>">
    <option value="post_title" <?php if($conf['sortby'] == 'post_title') echo $sel; ?>>
        Title
    </option>
    <option value="post_date" <?php if($conf['sortby'] == 'post_date') echo $sel; ?>>
        Date
    </option>
    <option value="ID" <?php if($conf['sortby'] == 'ID') echo $sel;? >>
        ID
    </option>
</select>

<!-- using WordPress selected(): -->
<label for="<?= $this->get_field_id('sortby'); ?>"><?php _e('Sort by:', 'wpdtree'); ?></label>
<select id="<?= $this->get_field_id('sortby'); ?>" name="<?= $this->get_field_name('sortby'); ?>">
    <option value="post_title" <?php selected($conf['sortby'], 'post_title'); ?>>Title</option>
    <option value="post_date" <?php selected($conf['sortby'], 'post_date'); ?>>Date</option>
    <option value="ID" <?php selected($conf['sortby'], 'ID'); ?>>ID</option>
</select>

/*  similar functions:
 checked() - compares two values and output the checked attribute for radio buttons / checkbox
 disabled() - =||= disables a form input field
*/