Shaobin Jiang

Change behavior of on_page_change

1

See [discussion](https://github.com/jspsych/jsPsych/discussions/3350). What this PR does: - `on_page_change` is called once at trial start - `current_page` is `null` if `on_page_change` is called at trial end - `on_page_change` receives second paramter...

## When used with `conditional_function` and the timeline is skipped ```javascript let jsPsych = initJsPsych({ show_progress_bar: true, message_progress_bar: (progress) => `${progress * 100}`, }); let trial = { type: jsPsychHtmlKeyboardResponse,...

The wiki overlaps with the README too much, with only a small proportion of additional information.