I still say the process as a whole is one of the weaker points of THREE.js at this point, but the animation system is becoming a little bit clearer to me.  I managed to get my guy running around (still with the horrible running animation) and he jumps when you press the space bar.  The running animation only triggers if the player is actually moving, so pressing ‘w’, ‘a’, ‘s’, or ‘d’.  The jumping animation will play whether the player is moving or not and you can’t jump again if a jump animation is currently in progress.  The jumping action is animation only, so there’s no way to jump “on top” of anything right now, you know, without any sort of collision detection.  All in all it’s pretty bad right now, but it’s a reasonable placeholder for better animations in the future.  Now I’ll make a sword attack animation and trigger it with left mouse clicks, then start working on getting some nasty little piggies running around Penrith Forest.