PHP Function To Get Alphabetical List Of Subdirectory

PHP function to get alphabetical list of subdirectori in a given subdirectory

<?php 

print_r(get_directories_list('')); // current directory
print_r(get_directories_list('uploads/'));

function get_directories_list($dir) {
	$files = glob($dir . "*");	 
	$dirs = array();
	foreach($files as $file) {
		if(is_dir($file)) {
			array_push($dirs, end(explode('/', $file)));
		}
	}
	sort($dirs);
	return $dirs;
}
?>