Test your site in various devices from an iPhone and iPad, to a Kindle and on Android on the Responsivetools. It also shows your site both in portrait and landscape mode. I like this tool much more because of the outlines of the devices displayed on the page, which brings more meaning to the whole process.
It is nothing mobile view or tablet view, rather it is the full desktop view in different size of screen (simply by setting frame size to those devices.) NO change in site kekekeek