This worked for me:
#!/usr/bin/env bash url='https://www.vpnbook.com/freevpn' html=$( curl -# -L "${url}" ) username=$( <<< "${html}" \ grep -P -o -e '(?<=<li>Username: <strong>)(.*?)(?=<\/strong><\/li>)' | head -n 1 ) password=$( <<< "${html}" \ grep -P -o -e '(?<=<li>Password: <strong>)(.*?)(?=<\/strong><\/li>)' | head -n 1 ) printf '%s\n' "Username: ${username}" "Password: ${password}"