Pangram checker

You are encouraged to solve this task according to the task description, using any language you may know.
A pangram is a sentence that contains all the letters of the English alphabet at least once.

For example:   The quick brown fox jumps over the lazy dog.



Task

Write a function or method to check a sentence to see if it is a   pangram   (or not)   and show its use.



Related tasks

   determine if a string has all the same characters
   determine if a string has all unique characters


s$ = "The quick brown fox jumps over the lazy dog."
Print pangram(s$);" ";s$
 
s$ = "My dog has fleas."
Print pangram(s$);" ";s$
 
function pangram(str$)
  str$  = lower$(str$)
  for i = asc("a") to asc("z")
      pangram = pangram + (instr(str$, chr$(i)) <> 0)
  next i
pangram = (pangram = 26)
end function