[document.write] no [innerHTML] depends [add/remove nodes] usually [0] 
Robust code
W 3 C s t a n d a r d
W o r k s i n a l m o s t a l l b r o w s e r s
H u m a n - r e a d a b l e c o d e
T e r s e c o d e
M o d u l a r c o d e
R o b u s t c o d e