Choose a peculiar typeface such as Arial Black or Helvetica Black as your preferred Western typeface.
Then look which lines below are displayed in Arial/Helvetica Black and which are not.
Also, choose different encodings from the menu "View > Character Encoding > More > ..."
Mozilla 1.7 does not recognize these language codes for the purpose of typeface selection: mn ps sd ur xx .
Firefox 2.0 does not recognize mn xx .
--:
0123456789 abcdefghijklmnopqrstuvwxyz
xx:
0123456789 abcdefghijklmnopqrstuvwxyz
en:
0123456789 abcdefghijklmnopqrstuvwxyz
el:
0123456789 abcdefghijklmnopqrstuvwxyz
be:
0123456789 abcdefghijklmnopqrstuvwxyz
bg:
0123456789 abcdefghijklmnopqrstuvwxyz
mk:
0123456789 abcdefghijklmnopqrstuvwxyz
mn:
0123456789 abcdefghijklmnopqrstuvwxyz
ru:
0123456789 abcdefghijklmnopqrstuvwxyz
sr:
0123456789 abcdefghijklmnopqrstuvwxyz
uk:
0123456789 abcdefghijklmnopqrstuvwxyz
he:
0123456789 abcdefghijklmnopqrstuvwxyz
yi:
0123456789 abcdefghijklmnopqrstuvwxyz
ar:
0123456789 abcdefghijklmnopqrstuvwxyz
fa:
0123456789 abcdefghijklmnopqrstuvwxyz
ps:
0123456789 abcdefghijklmnopqrstuvwxyz
sd:
0123456789 abcdefghijklmnopqrstuvwxyz
ur:
0123456789 abcdefghijklmnopqrstuvwxyz
hi:
0123456789 abcdefghijklmnopqrstuvwxyz
mr:
0123456789 abcdefghijklmnopqrstuvwxyz
ne:
0123456789 abcdefghijklmnopqrstuvwxyz
sa:
0123456789 abcdefghijklmnopqrstuvwxyz
th:
0123456789 abcdefghijklmnopqrstuvwxyz