There are a few ways to debug a mobile website. The first few ways are provided by Apple and Google and allow you to connect your mobile device to your computer and use Safari and Chrome's development tools to see the source of the application.
Apple: Enable Web Inspector through the Settings > Safari settings on the device and then use Safari on the desktop to inspect the elements.
Google: Enable the developer options on the device, install drivers if needed on the desktop, and then launch Chrome on the desktop and navigate to about:inspect and connect to the device with the DevTools .
Another way is to use testing tools made by the company I work for, Mobile Labs. We provide a private secure mobile testing cloud (an alternative to Device Anywhere) called deviceConnect as well as an automated testing tool that provides the ability to test mobile websites, web apps, hybrid apps, as well as native apps.
You can learn more here: http://mobilelabsinc.com/solutions/