Guitar Notes on Fretboard?

Question: Guitar Notes on Fretboard!?

I'm a bit unsure as to why there are no E# or B# on the fretboard!. I know you going up by a semi-tone but why are these not included!?

Here's the link to the fretboard:
http://www!.guitarnoise!.com/faq!.php!?id=12!.!.!.Www@QuestionHome@Com

Best Answer - Chosen by Asker:

There's no E# or B# on any instrument (notice the keyboard on a piano doesn't have black keys between all the white ones)
E# (1/2 step up from E) would be the same note as F!. B# is the same note as C!.Www@QuestionHome@Com

E# is F natural and B# is C natural!.!.!. just like on a pianoWww@QuestionHome@Com