Hallo, I try to send a message from a pdf to a webserver. This works fine, unless the URL has a `#' in it. Then TeX throws an error: ! Illegal parameter number in definition of \!!stringa I tried to work around it with \edef'ing a \doublecross macro which expands to \char35, but this did not work. I also tried some extensive use of \noexpand and \expandafter, but it failed, too. Obviously, there's some \csname...\endcsname stuff going on when creating the URL. TIA, olli Here's a minimal example: \setupcolors[state=start] \setupinteraction[state=start] \starttext \definefield[shorttext] [line] [ShortLine] [] [] \setupfield [ShortLine] [label,frame,horizontal] [frame=off] [height=18pt,width=15em,align=middle,frame=off] [height=18pt,width=20em,align=right,style=\tfx,,frame=on] \field[shorttext][Bitte geben Sie einen Text ein:] \blank \button[]{Abschicken}[SubmitForm{http://mydomain.test/formular#fdf,Shortline}] \stoptext