Links2 is a text browser similar to the venerable Lynx. It can also render in a GUI window with images.
It can be installed from the Ubuntu archives:
$ sudo apt install links2
To open webpage in GUI window:
Blazing fast. Noticeably faster than all other GUI browsers.
Do not expect anything other than simple HTML support.
Probably the best option for viewing offline documentation. Remember that the HTML has to be very simple.
Tried with: Links2 2.8 and Ubuntu 14.04