require_title_for_cpt_4.php

/*
 * Require post title when adding/editing a Project Summary
 */
function rpt_require_post_title_for_custom_post_type() {
	global $post;

	// only run the code below if this is a "project_summary" post type
	if ( 'project_summary' == $post->post_type ) {
		?>
		<script type='text/javascript'>
			(function ($) {
				$('body').on( 'submit.edit-post', '#post', function () {
					
					// If the title isn't set
					if( $("#title").val().replace(/ /g,'').length === 0 ) {

						// Show a popup box that says "A title is required."
						alert('A title is required.');

						// Hide the spinner
						$('#major-publishing-actions .spinner').hide();

						// The buttons get "disabled" added to them on submit. Remove that class.
						$('#major-publishing-actions').find( ':button, :submit, a.submitdelete, #post-preview' ).removeClass( 'disabled' );

						// Focus on the title field.
						$("#title").focus();

						return false;
					}
				});
			}(jQuery));
		</script>
		<?php
	}
}
add_action( 'admin_print_footer_scripts', 'rpt_require_post_title_for_custom_post_type' );