Request URL m3u8 Javascript or PHP

a code similar to that extension, https://chrome.google.com/webstore/detail/video-m3u8-sniffer-find-h/akkncdpkjlfanomlnpmmolafofpnpjgn/related, but I don't want an extension, just a simple, variable code that stores the url of the chosen website and a variable for the video link. I just want it to get the "request url" link and store it in a variable.