Today, with 3.0, building a responsive Ning Network means constantly testing how it displays across mobile and tablet devices. You could resize the browser yourself, or use a browser extension or tools within your IDE; but there is an ultra-simple tool that allows you to see how a page displays on different screen sizes, in a single view. The Responsive Web Design Tool from Matt Kersley works by entering your website's URL into the address bar to test a specific page. The screen and device options are 240 x 320 (small phone), 320 x 480 (iPhone), 480 x 640 (small tablet), 768 x 1024 (iPad – Portrait) and 1024 x 768 (iPad – Landscape). However, the content width cannot be pixel-perfect, as 15 pixels have to be added to the frame to accommodate the scrollbars.
In this example i used my Mobile 2.0 site
You can share the results of the test with others by adding any URL to the end of the testing page address (e.g. http://mattkersley.com/responsive/?mashable.com). One major benefit of this tool is that it can be self-hosted (available on GitHub) by downloading and installing it on your own site. You can then navigate through the frames that your website appears in, testing the entire site effortlessly.