add_action( 'admin_head-post-new.php', 'wpse_59770_publish_admin_hook' );
add_action( 'admin_head-post.php', 'wpse_59770_publish_admin_hook' );
add_action( 'wp_ajax_wpse_59770_pre_submit_validation', 'wpse_59770_ajax_pre_submit_validation' );

function wpse_59770_publish_admin_hook()
{
    global $current_screen;
    if( 'page' != $current_screen->post_type )
        return;

    ?>
    <script>
        jQuery(document).ready(function() {
            jQuery('#publish').click(function() 
            {
            	jQuery('#publishing-action #ajax-loading').css('visibility', 'visible');
                var data = {
                    action: 'wpse_59770_pre_submit_validation',
                    security: '<?php echo wp_create_nonce( 'pre_publish_validation' ); ?>',
                };
                jQuery.post(ajaxurl, data, function(response) 
                {
                    // OK, save page
                    if (response=='true') {
                        jQuery('#publish').removeClass('button-primary-disabled');
                        jQuery( "#publish" ).click()
                    }
                    // Not OK, display alert message
                    else
                    {
                        alert(response);
                        jQuery('#ajax-loading').css('visibility', 'hidden');
                        jQuery('#publish').removeClass('button-primary-disabled');
                        return false;
                    }
                });
                return false;
            });
        });
    </script>
    <?php
}


function wpse_59770_ajax_pre_submit_validation()
{
    //simple Security check
    check_ajax_referer( 'pre_publish_validation', 'security' );

    echo 'true'; 
    die();
}