How to make a platform fall down after stepping on it?

Questions & Answers
1

There are a few platforms. After the player moves from one platform to another the first one is supposed to fall. The platform that the player is on is supposed to remain still until the player moves to another one. The idea is that the character/player can’t return to a platform he was already on.
What I tried:
#pragma strict

function OnCollisionEnter(Char){
GetComponent.().useGravity = true;
}

I put this script on the platforms but they start to fall as soon as I step on them.

2

Use this Unity - Scripting API: MonoBehaviour.OnCollisionExit(Collision)

3

Use OnCollisionExit so the platform falls after the player exits the area and you also can use a timer to delay it more

function OnCollisionExit (player : Collider) {
	if (player.gameObject.tag == "Player"){

		 GetComponent.().useGravity = true;

}

	}

if you want a delay you can make a variable true on collision exit and use it in Update function to trigger a timer to activate gravity

var DestroyPlat : boolean = false;	

function OnCollisionExit (player : Collider) {
	if (player.gameObject.tag == "Player"){
		 DestroyPlat = true;

}

	}

function Update(){
if (DestroyPlat){

   //assuming the delay will be 1 sec
	if(delay <= 1){
	       delay += Time.deltaTime;	
    }
	else if (delay > 1){
			DestroyPlat = false;
			delay =0;
		       GetComponent.().useGravity = true;
	}
	
	}

}