This is a test, sorry.
X: 1
K: perc stafflines=1
L:1/4
B2 B2|B z B z|B1/2 z1/2 z B1/2 z1/2 z|B1/4 z3/4 z B1/4 z3/4 z|]
A following test:
X: 1
L:1/8
K: perc stafflines=1
z B z B|z B z B|]
And another:
X: 1
L:1/8
K: perc stafflines=1
B B - B B ||-B B2 B-|]
Final one:
X: 1
L:1/8
K: perc stafflines=1
B z B z|B z B z|]
Still trying to understand what's wrong with the above (see the related post).
EDIT:
Ok, it seems like the initial X: 1 is always required.
Still, it would really help if ABCjs would work within the editor preview too. Note that editing a previous post may give inconsistent result, and page refresh seems to be always required for some reason.