http://bugs.winehq.org/show_bug.cgi?id=26591
--- Comment #9 from Nikolay Sivov bunglehead@gmail.com 2011-03-31 12:28:50 CDT --- As expected it's relative:
--- 002f:trace:msxml:httprequest_open (0xbcfdac0)->(L"GET" L"Scripts/Common.js" {VT_BOOL: 0}) ---
Our implementation doesn't support relative url for this method yet. Some tests are here though, so there's an understanding how it's supposed to work at least.