Stop rotation of camera at certian degree

Ok so here is my third attempt but with no success. right now it just freezes the game after a few seconds and does not look any where just straight up. Is there something I missing with this? I am basing it off the mouse look at script in the standard assets. Here is what I have so far: Thanks for any help with this

 var turnSpeed : float = 15f;
 
 var minX :float = -90;
 var maxX : float = 90;
 
 var minY : float = -90;
 var maxY :float = 90;
 
 var rotationX : float = 0f;
 var rotationY : float = 0f;
 var originalRotation : Quaternion;
 var xQuaternion : Quaternion;
 var yQuaternion : Quaternion;
 
 
 function Start () {
 
 }
 
 function Update () {
     
     
     //rotate the comera
     //this works
     this.transform.RotateAroundLocal(Vector3.up, Input.GetAxisRaw("Vertical") * turnSpeed);
     this.transform.RotateAroundLocal(Vector3.forward, Input.GetAxisRaw("Horizontal") * turnSpeed);
     
     
     if(Input.GetAxis("Vertical"))
     {
         rotationX += Input.GetAxis("Vertical") * turnSpeed;
         rotationX = ClampAngle(rotationX, minX, maxX);
     }
     if(Input.GetAxis("Horizontal"))
     {
         rotationY += Input.GetAxis("Horizontal") * turnSpeed;
         rotationY = ClampAngle(rotationY, minY, maxY);
     }
     
     xQuaternion = Quaternion.AngleAxis (rotationX, Vector3.up);
     yQuaternion = Quaternion.AngleAxis (rotationY, -Vector3.right);
     transform.localRotation = originalRotation * xQuaternion * yQuaternion;
          
      
 }
 
  static function ClampAngle(angle :float, min : float , max :float )
     {
         if (angle < -360F)
             angle += 360F;
         if (angle > 360F)
             angle -= 360F;
         return Mathf.Clamp (angle, min, max);
     }