Most Mac users have a go-to browser; whether Safari, Mozilla Firefox, or Google’s Chrome. Website developers have slightly different requirements, especially with the rapid growth of so-called Responsive Web Design, a new technique which alters a website’s display depending upon which device is being used to view the site.
Website developers want to see how their designs are viewed in a regular browser window, and in a mobile browser window. That’s what the Duo app does. Both at the same time.
Here’s an example of the dual-pane at work.
Duo’s window is easily resized to accommodate your Mac’s screen. The left pane displays the mobile device view and it can be resized, too. The right pane defaults to standard desktop view (though the left side can also be resized to see how the page looks on a tablet).
Code can be debugged in each window pane. Cache is easily cleared using keyboard shortcuts (including cookies), and both sides display the same webpage at the same time, and both are refreshed simultaneously. Click on a link in one window pane and both panes open to the new page.
Duo is a good way, but one of many, to check responsive web page design. Toolbar options are minimal and one click to the Menubar clears cache and cookies at the same time, making for an easier refresh. Duo doesn’t cost much, either, and the developer has a nice video to show you exactly how the app works.