When taking a screenshot of a web page, we face the difficulty of how to grab the whole page into a single screen capture. Usually a web page doesn't fit into the size of our computer screen forcing us to take several screenshots while scrolling down. To deal with this requirement, there are various tools and browser plug-ins are available. However, recently I found a very nice way to do it using a built-in functionality of Firefox web browser. May be it is important to mention that I did it on a computer running Ubuntu 14.04 64-bit version.
Here's how we do it.
While we are in the required web page on Firefox web browser, use the key combination Shift+F2 to get a text field at the bottom of Firefox window which is a kind of command line to interact with it. On this text field, type screenshot --fullpage and hit Enter. This action will take a full page screenshot and save it to the Downloads directory. If any unnecessary advertisement or a banner is troubling you, it's better to use some ad blocking plug-in for Firefox first. I use Adblock Plus plug-in.