OnTiggerEnter/OnTriggerExit is called twice

I'm trying to increase an integer by 1 whenever the player collides with a trigger, but instead it increases by 2, which means the function is called twice. I put comments next to where I made necessary changes to get what I want. But I'm asking this for several purposes in the future. Here's the code:

Code (csharp):

1. var PortalActive : boolean = false;
2.  
3. static var PortalCount : float = 0; //Was originally int, but I changed it so it accepts 0.5
4.  
5. function Start () {
6.     gameObject.renderer.material.color.a = 0.75f;
7. }
8.  
9. function OnTriggerExit (collision : Collider) {
10.  
11.     if (collision.gameObject.FindWithTag ("Player")) {
12.         if (!PortalActive) {
13.             PortalActive = true;
14.        
15.             gameObject.renderer.material.color = Color (0, 1, 0, 0.75);
16.             gameObject.particleSystem.startColor = Color.green;
17.  
18.             PortalCount += 0.5; //Was originally 1, but I changed it to 0.5 so I can get 1
19.            
20.         }
21.     }
22. }

 

for a start, change
if (collision.gameObject.FindWithTag ("Player")) {
to
if (collision.gameObject.tag == "Player") {
Doesn't make sense to perform a find operation when you already have a reference to the object

Is there only one instance of this script?

 

Whoops, it turns out that I added the script twice.

Thanks for pointing that out.