Often, when coding a responsive site, you have to use the "Responsive Mode" in browsers. This simplifies and speeds up the development itself. But not always on mobile devices everything looks like in a simulator on a desktop. For such cases, it will be useful to debug web applications on a mobile device.
First, you need to set up a device in which you can run and / or debug the application. It can be either a smartphone or a tablet connected to a personal computer via USB or Wi-Fi. Let's consider an example of setting using the Firefox browser (version 39 or higher).