I created a new page per this https://wiki.phpbb.com/Tutorial.Adding_pages
The page has a simple <form action back to the page, a textarea and buttons to Save or Cancel editing of textarea.
how do I detect that it is a post back?
how do I detect it is a get with query string after the URL?
where do I insert java script in the Head for this page only?
Since per the instructions the template is at /phpBB3/language/<lang>/mods/my_language_file.php is what is best way to code the action URL?
How do I grab the contents of the textarea so I can write to file?