check the post has children #WordPress

gistfile1.php

<?php
/**
 * Usage
 * if ( has_children( get_the_ID() ) ) :
 *     // this post has children
 * else:
 *     // this post has no children
 * endif;
 */
function has_children( $post ) {
	$post = get_post( $post );
	if ( !$post || is_wp_error( $post ) )
		return false;
	$children = get_pages("child_of=".$post->ID);
	if ( count( $children ) != 0 ) { return true; } // Has Children
	else { return false; } // No children
}