Can stand up beneath a collider

Here is your code i edited its untested but i think it should work. For a detailed explanation just ask :) to edit how much room you need change the needStandRoom variable.

 Var crouchSpeed : float = 3;
 static var crouched : boolean = false;
 static var moving : boolean = false;
  
 private var Speed : float = 1;
 private var chMotor: CharacterMotor;
 private var ch: CharacterController;
 private var tr: Transform;
 private var height: float;
 
 var distFromUp : float;
 var canStand : boolean = false;
 var needStandRoom : float = 3;
  
 function Start(){
     chMotor = GetComponent(CharacterMotor);
     tr = transform;
     ch = GetComponent(CharacterController);
     height = ch.height
 }
  
 function Update(){
  
     var h = height;
     var speed = Speed;
  
     if (Input.GetButton("Jump") && canStand){
         crouched = false;
     }
     if (Input.GetKeyDown(KeyCode.LeftControl) || Input.GetKeyDown(KeyCode.RightControl)){
         crouched = !crouched;
     }
     if (crouched){
         h = 0.5 * height;
         speed = crchSpeed;
     
     var hit : RaycastHit;
 
     if(Physics.Raycast(transform.position,Vector3.up,hit))
     {
     
     
     if(hit.collider.gameObject)
     {
 
     distFromUp = Vector3.Distance(transform.position,hit.point);
     
         if(distFromUp < 3)
         {
         canStand = true;
         }else{
         canStand = false;
         }
     
 
     }else{
     canStand = true;
     }
     
 
     }
 
 
     }
     chMotor.movement.maxForwardSSpeed = speed;
     chMotor.movement.maxSidewaysSpeed = speed -0.5;
     chMotor.movement.maxBackwardsSpeed = speed -1;
     var lastHeight = ch.height;
     ch.height = Mathf.Lerp(ch.height, h, 5*Time.deltaTime);
     tr.position.y += (ch.height-lastHeight)/2
 }