Charge/AoO question

[Thanatosia]

Issue that came up in our game tonight.

We had a monk who had enlarge person in effect, giving him a 10ft reach. An opponent charged him, and the monk used his 10ft reach to trigger an attack of opportunity against the charge to make a trip attack. Does the trip attack cause the charger to fall 10ft away, or since it triggers 'on leaving' the threatened square 10ft out, does he make it to the square 5ft/adjacent away from the monk, and if he makes it to the final square, does he still get to make his charge attack, or can he make a standard attack (possibly from prone) if the charge is foiled?

[Andezzar]

AoOs occur before the triggering condition happens. The triggering condition here is leaving a threatened square. The monk with the reach weapon threatens the adjacent square and the one beyond that. So if trip attempt is successful the charger falls in the latter square. Since the charger has used his full round action to charge he does not have a standard action to perform an attack, he is also out of reach.

This would have been a good question for the Simple Question thread.