PHP Code:
If TextBox1.Text = "a" Or "A" Or "b" Or "B" Or "c" Or "C" Or "d" Or "D" Or "e" Or "E" Or "f" Or "F" Or "g" Or "G" Or "h" Or "H" Or "i" Or "I" Or "j" Or "k" Or "K" Or "J" Or "l" Or "L" Or "m" Or "M" Or "n" Or "N" Or "o" Or "O" Or "p" Or "P" Or "q" Or "Q" Or "r" Or "R" Or "s" Or "S" Or "t" Or "T" Or "u" Or "U" Or "v" Or "V" Or "w" Or "W" Or "x" Or "X" Or "y" Or "Y" Or "z" Or "Z" Then
TextBox1.Clear()
MsgBox("BUCHSTABEN NICHT ERLAUBT !")
