meta title custom fields

@@h@ this part goes into functions.php

// 'Custom Meta Title' field below post/page editor
add_action('admin_menu', 'custom_meta_title');
add_action('save_post', 'save_custom_meta_title');
function custom_meta_title() {
add_meta_box('custom_meta_title', 'Add meta title <small>(if left empty, blabla)</small>', 'custom_meta_title_input_function', 'post', 'normal', 'high');
add_meta_box('custom_meta_title', 'Add meta title <small>(if left empty, blabla)</small>', 'custom_meta_title_input_function', 'page', 'normal', 'high');
}
function custom_meta_title_input_function() {
global $post;
echo '<input type="hidden" name="custom_meta_title_input_hidden" id="custom_meta_title_input_hidden" value="'.wp_create_nonce('custom-meta-title-nonce').'" />';
echo '<input type="text" name="custom_meta_title_input" id="custom_meta_title_input" style="width:100%;" value="'.get_post_meta($post->ID,'_custom_meta_title',true).'" />';
}
function save_custom_meta_title($post_id) {
if (!wp_verify_nonce($_POST['custom_meta_title_input_hidden'], 'custom-meta-title-nonce')) return $post_id;
if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE) return $post_id;
$customMetatitle = $_POST['custom_meta_title_input'];
update_post_meta($post_id, '_custom_meta_title', $customMetatitle);
}

@@h@ this part goes into header.php to replace the <title>....</title> section

<title><?php
if( is_single() || is_page() ) :
    $text = get_post_meta($post->ID,'_custom_meta_title',true);
    if( $text ) :
    echo esc_attr( $text );
    else :
    wp_title( '|', true, 'right' ); //default if no custom field input
    endif;
else :
wp_title( '|', true, 'right' ); //any other than single post or page
endif; ?></title>