F12 Developer Tools
F12 Developer Tools were introduced in Windows Internet Explorer 8, and updated with new functionality in Windows Internet Explorer 9. F12 Developer Tools in Internet Explorer 10 add Web Worker debugging and support for multiple script sources.
In this section
Using four new console methods, apps can send properties of an object to the console, clear messages in the console, and start and stop profiling in the Microsoft Visual Studio debugger.
To help improve user interface performance, Web Workers enable you to run processor-intensive code off the main thread of execution to separate threads. F12 Developer Tools now can also help you debug these threads, letting you view individual worker scripts, set breakpoints, and watch variables.