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


 
pangram = 0
s = "The quick brown fox jumps over the lazy dog."
see "" + pangram(s) + " " + s + nl
 
s = "My dog has fleas."
see "" + pangram(s) + " " + s + nl
 
func pangram str
     str  = lower(str)
     for i = ascii("a") to ascii("z")
             bool = substr(str, char(i)) > 0
             pangram = pangram + bool
     next 
     pan = (pangram = 26)
     return pan
 