Multiple Keypress Doesn't Work Up Left And Space?

I have a strange problem when I press up left arrows and space simultaneously.Why the space doesn't work? I tryed to test here http://jsfiddle.net/vor0nwe/mkHsU/ and there is the

Solution 1:

This is actually probably your keyboard, it's a phenomenon called "Key Ghosting", certain key combinations wont work on some keyboards.