Here's a quick one, but I've had to look this up more than once, so I thought I better blog about it
As a beginner, one of my biggest pet peeves about working with iOS, was not being able to see the line number that caused an error in the debugger.
Remember that the scope of 'this' will be global when your callback function runs in setTimeout(), setInterval(). or requestAnimationFrame().
This took me longer to figure out than it should have.
Quick Tip - Keyboard and becomeFirstResponder
To see a few posts on Android, visit the old blog site. Hope to get back to android development soon.
If you're a web developer looking for a quick introduction to 3D graphics, then this is the book for you.
Here's an interesting little observation I made about the detach() method