You mean on Firefox for Android? There is not a built-in feature for this, but there is an add-on you can install. menu > Tools > Add-ons > Browse all Firefox Add-ons Then search for View Source Mobile ---- To use only internal facilities, you can try this: '''(1) Set up wrapping of long lines (this is a one-time operation)''' (A) Open a new tab to '''about:config''' (type about:config in the Awesomebar and tap the go arrow or tap Enter). ''You may want to bookmark this for easier future access.'' (B) In the search box, type '''view_''' and pause while Firefox filters the list (C) Scroll down to '''view_source.wrap_long_lines''' and tap Toggle to switch it from false to true. You're done with about:config. '''(2) To view the "original" source of the currently displayed page in the current tab in place of the page''' ''Note: original source is the source sent from the server before it was modified by scripts. Obviously as you scroll down on Facebook, scripts pull in more data. That is not in the original source.'' Edit the address of the page as follows: (A) Tap the address bar and Firefox should select the entire address. Tap again and move the insertion point to the beginning. (B) Type or paste '''view-source:''' before the address and tap the go arrow to load the source. (C) Squint at the tiny source code!