下面哪种操作不属于跨域
http://www.123.com/index.html 调用 http://www.456.com/server.php
http://www.123.com/index.html 调用 https://www.123.com/server.php
http://www.123.com:8080/index.html 调用 http://www.123.com:8081/server.php
http://www.123.com/index.html 调用 http://www.123.com/server.PHP
