Rotation Constraint doesn't work properly

I am trying to use rotate constraint with the following script but nothing seems o happen. Can anyone tell me the easiest way to limit the rotation of a camera attached to object so it won't go through the floor.

Here is my current script I thought was closest to my goal from another post. but it doesn't respond to inspector limits.

 var target : Transform;
 var distance = 10.0;
 var xSpeed = 250.0;
 var ySpeed = 120.0;
 var yMinLimit = -20;
 var yMaxLimit = 80;
 var xsign =1;
 
 private var x = 0.0;
 private var y = 0.0;
 
 @script AddComponentMenu("Camera-Control/Mouse Orbit")
 function Start()
 {
     var angles = transform.eulerAngles;
     x = angles.y;
     y = angles.x;
 
     var rotation = Quaternion.Euler(y, x, 0);
     // /!\ This is the equivalent of transform.forward * -distance + target.position
     // You're sure that's what you want ?
     // By the way, those for lines are identical to those in LateUpdate, you should
     // never have twice the same thing when you code, use a function instead.
     var position = rotation * Vector3(0.0, 0.0, -distance) + target.position;
     transform.rotation = rotation;
     transform.position = position;
 }
 
 function LateUpdate()
 {
     //get the rotationsigns
     // /!\ Those are transform.up and target.up.
     var forward = transform.TransformDirection(Vector3.up);
     var forward2 = target.transform.TransformDirection(Vector3.up);
 
     if (Vector3.Dot(forward,forward2) < 0)
         xsign = -1;
     else
         xsign =1;
 
     for (var touch : Touch in Input.touches) 
     {
         if (touch.phase == TouchPhase.Moved) 
         {
             x += xsign * touch.deltaPosition.x * xSpeed *0.02;
             y -= touch.deltaPosition.y * ySpeed *0.02;
 
             var rotation = Quaternion.Euler(y, x, 0);
             var position = rotation * Vector3(0.0, 0.0, -distance) + target.position;
             transform.rotation = rotation;
             transform.position = position;
         }
     }
 }