4
I just solved it on my own~
besides that php5 does not include that extension in default, I also inputted the wrong username and password...
So check these two if you get that blank page, though I am not sure about that
but then I got the same problem with this:
https://xoops.org/modules/newbb/viewtopic.php?topic_id=34839&forum=1
(cycling in entering the admin section)
Solving...
Hope you won't get that problem~
p.s. I come from China too, but more accurately from Hong Kong