Wordpress Subheading plugin tab order fix

functions.php

/**
 * Inject javascript to fix tab order for Subheading plugin input field
 */
function add_jquery_data() {
	// only load on new post / edit post page
	global $parent_file;
	if ( is_admin() && $parent_file == 'edit.php'): ?>
		<script type="text/javascript">
			jQuery(document).on('ready', function(){
				var titleInput = jQuery('input#title')
				  , subInput = jQuery('#wp_subheading');
				if (subInput.length){
					titleInput.off('blur keydown');
					titleInput.one('keydown',function(event){
						jQuery('#title-prompt-text').addClass('screen-reader-text');
					});
					titleInput.on('keydown',function(event){
					    var keyCode = event.keyCode || event.which;
						if(keyCode == 9) {
							event.stopPropagation();
							event.preventDefault();
						    if(event.shiftKey) {
						       //Focus previous input
						    }
						    else {
						       //Focus next input
						       subInput.focus();
						    }
						}
					});
					titleInput.on('blur',function(event){
						if(!this.value){
							jQuery('#title-prompt-text').removeClass('screen-reader-text');
						}
					});
					subInput.on('keydown',function(){
						var keyCode = event.keyCode || event.which;
						if(keyCode == 9) {
						    event.stopPropagation();
						    event.preventDefault();
						    if(event.shiftKey) {
						       //Focus previous input
						       titleInput.focus();
						    }
						    else {
						       //Focus next input
						       tinyMCE.get('content').focus();
						    }
						}
					});
				}
			});
		</script>
	<?php endif;
}
add_filter('admin_footer', 'add_jquery_data');