I recently installed the 64 bit version of Ruby 2.0 on my Windows 8 machine.
All of my old projects I tested with it ran just fine and the world was a happy place.
Then I had to install Rails, so that I could make some minor changes to an existing app … and the pain began.
Imagine you have an element which is dynamically added to your web page (an image in a lightbox, for instance) and you want to centre it on the screen both horizontally and vertically.
You could do so with CSS (as this article explains), but if you don’t know the dimensions of the element you want to centre or you need to support older browsers, things can become quite tricky quite quickly.