urlIn$ = "http://foo bar/"

for i = 1 to len(urlIn$)
  a$ = mid$(urlIn$,i,1)
  if (a$ >= "0" and a$ <= "9") _
  or (a$ >= "A" and a$ <= "Z") _
  or (a$ >= "a" and a$ <= "z") then url$ = url$ + a$ else url$ = url$ + "%"+dechex$(asc(a$))
next i
print urlIn$;" -> ";url$