Test XMLHttpRequest responseURL.

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".

req.readyState = 0: responseURL = 
PASS req.responseURL is ""
req.readyState = 1: responseURL = 
PASS req.responseURL is ""
req.readyState = 1: responseURL = 
PASS req.responseURL is ""
req.readyState = 2: responseURL = http://127.0.0.1:8000/xmlhttprequest/resources/basic-auth/basic-auth.php?uid=async
req.readyState = 3: responseURL = http://127.0.0.1:8000/xmlhttprequest/resources/basic-auth/basic-auth.php?uid=async
req.readyState = 4: responseURL = http://127.0.0.1:8000/xmlhttprequest/resources/basic-auth/basic-auth.php?uid=async
PASS req.responseURL is "http://127.0.0.1:8000/xmlhttprequest/resources/basic-auth/basic-auth.php?uid=async"
PASS successfullyParsed is true

TEST COMPLETE