Recently I discovered a tool which can be very useful for web development and testing: it's called Jolly and it's an app for Mac OSX.
Normally the prototyping and front-end web-development process looks like that: you code, save your project, reload your browser, check how the website looks on different screens either by using a bookmarklet or by setting up a local server and opening the website on other devices. Then you code again, save, reload, save, reload and so on. This can get cumbersome with multiple browsers and multiple devices. What if you need to test your design on an iPad, an iPhone, an Android phone, an Android tablet, a Windows phone and so on? This is especially important for cross-browser testing and testing responsive designs simultaneously on multiple devices.
Jolly solves this problem by delivering the changes simultaneosly and accross multiple devices. Define the project folder for Jolly to observe, open the generated link on all the browsers and devices (in the same wireless network) and see your changes flow automatically while you code.. Jolly performs its work independently. You are free to choose whatever development or design tool you like. Jolly will reload your project as soon as it detects a change in the project folder you specified.
It's even possible to "wiretrap" your prefered server technology.
Here is the video showing what Jolly does: http://www.youtube.com/watch?v=2Onqtpqvd7w
Jolly is available in the Mac App Store: https://itunes.apple.com/us/app/jolly/id567804958?ls=1&mt=12