ENCODE: This function receives an URL-type value as an
argument and encodes it. This is necessary when different characters
to those accepted by URLs are to be used. This function
automatically transforms invalid characters into their corresponding
TOURL: This function receives a string-type value representing an
URL, and returns it converted into an URL-data type value.
URLTOSTRING: This function receives an URL-type value as an
argument and obtains its content as a string value.