Javascript Call PHP in Sister Folder

I have the following tree:

root
  -js_src
  -php_src
  -images

Now, how do i reliably call the PHP files f开发者_如何学运维rom the Javascript? The PHPs are located in the php_src folder while the javascript is in the js_src folder.

Absolute URL:    http://yourserver.com/php_src/script.php
Relative-rooted: /php_src/script.php

File-based relative: ../php_src/script.php
File-based absolute: /path/to/your/site/php_src/script.php