WordPress - get the slug of your post or page

functions.php

<?php
/**
 * Get the slug of your post or page
 *
 * @author Tom Barrett
 * @link http://goo.gl/95boK0
 */
function iweb_get_the_slug( $id = null ) {
	if ( empty( $id ) ) {
		global $post;

		if ( empty( $post ) ) {
			return ''; // No global $post var available
		}

		$id = $post->ID;
	}

	$slug = basename( get_permalink( $id ) );

	return $slug;
}