enc$ = URLENCODE(text$)
Returns a string in which all non-alphanumeric characters except -_. have been replaced with a percent (%) sign followed by two hex digits and spaces encoded as plus (+) signs. It is encoded the same way that the posted data from a WWW form is encoded, that is the same way as in application/x-www-form-urlencoded media type.
LOCAL enc$ = URLENCODE$("?firstname.lastname@example.org&text=some/special\nchars")
STDOUT enc$ + "\n"
STDOUT URLDECODE$(enc$) + "\n"