Confirm on Add / Edit Feature on PHPRUNNER on a large project

Personally I believe this is a very bad usability feature. It does nothing useful but prevents users from clicking on Save button accidentally. I would understand adding it to a few pages with very important info but adding it to each page is a usability nightmare.
There are other ways to achieve the same functionality like client and server side validation, saving a copy of old data in another table for archive purposes, option to undo. For example, on Amazon orders are placed to the queue where you can cancel or modify them for some period of time, until it shipped.
Sorry, there is no way to add this option to all pages at once rather than modifying source. Check files AddPage.js and EditPage.js in source\include\common\runnerJS\pages folder.
Function saveHn() is the one that prepares form and submits data. You can try to inject your own code there.