Crosshair Fade on Zoom

Hello, I'm working on a FPS survival game, and I want to make a Zoom function were I use Field of View with a Weapon-Zoom animation. But how would I fade away the crosshair one MouseDown? Also why won't my animations work?

 //attach this script to the object you want the animations to play on when 
 
 //clicking the Left mouse button.
 
 
 //Remember the name of your animations!
 
 
 function Update ()
 
 {
 
    if (Input.GetButtonDown("Fire1")) 
 
     {
 
        animation.CrossFade ("Shot"); 
     }
 
       
 
        else if (Input.GetButtonDown("Fire2")) 
     {
 
        animation.CrossFade ("Zoom_In"); 
 
     }
 
     
 
    else
 
     {
 
       animation.CrossFade ("Idle");
 
     }
     
 
     
 }