Loading CDN-hosted jQuery with triple fallbacks in PHP

loadjquery.php

<?php

// ref: http://www.php.net/manual/ja/function.file-exists.php#79118
function getResource(){
  $args_last_key = func_num_args() - 1;

	$resource_urls = array_slice(func_get_args(), 0, $args_last_key);
	// The last argument is a local file path.
	$local_fallback = func_get_arg($args_last_key);
	
	foreach($resource_urls as $url){
		//参考 http://www.php.net/manual/ja/function.file-exists.php#79118
		$handle = curl_init($url);
		if(false === $handle){
			continue;
		}
		curl_setopt($handle, CURLOPT_HEADER, false);
		curl_setopt($handle, CURLOPT_FAILONERROR, true);  // this works
		curl_setopt(
			$handle,
			CURLOPT_HTTPHEADER,
			array("User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.15) Gecko/20080623 Firefox/2.0.0.15")
		); // request as if Firefox
		curl_setopt($handle, CURLOPT_NOBODY, true);
		curl_setopt($handle, CURLOPT_RETURNTRANSFER, false);
		$connectable = curl_exec($handle);
		curl_close($handle);
		if($connectable){
			return print str_replace(array("http:", "https:"), "", $url);
		}
	}
	
	echo $local_fallback;
	return false;
}

?>

usage_example.php

<?

define('JQ_VER', '1.9.1');
echo "<script src=\"";
getResource(
	"https://ajax.googleapis.com/ajax/libs/jquery/".JQ_VER."/jquery.min.js",
	"http://code.jquery.com/jquery-".JQ_VER.".min.js",
	"http://ajax.aspnetcdn.com/ajax/jQuery/jquery-".JQ_VER.".min.js",
	"js/jquery.js"
);
echo "\"></script>\n";

?>