Norse Gods Can't Jump

I have come to the horrible conclusion that I cannot figure how to get my character to jump :(, I have tried multiple scripts with multiple variations of those scripts, for example;

private var walkSpeed : float = 1.0;
private var gravity = 100.0;
private var moveDirection : Vector3 = Vector3.zero;
private var charController : CharacterController;


function Start()
{
charController = GetComponent(CharacterController);
animation.wrapMode = WrapMode.Loop;
}


function Update ()
{
if(charController.isGrounded == true)
{
if(Input.GetAxis("Vertical") > .1)
{
if(Input.GetButton("Run"))
{
animation.CrossFade("run");
walkSpeed = 25;
}
else
{
animation["walk"].speed = 1;
animation.CrossFade("walk");
walkSpeed = 6;
}
}
else if(Input.GetAxis("Vertical") < -.1)
{
animation["walk"].speed = -1;
animation.CrossFade("walk");
walkSpeed = 6;
}
else
{
animation.CrossFade("idle");
}


// Create an animation cycle for when the character is turning on the spot
if(Input.GetAxis("Horizontal") && !Input.GetAxis("Vertical"))
{
animation.CrossFade("walk");
}


transform.eulerAngles.y += Input.GetAxis("Horizontal");
// Calculate the movement direction (forward motion)
moveDirection = Vector3(0,0, Input.GetAxis("Vertical"));
moveDirection = transform.TransformDirection(moveDirection);

}

moveDirection.y -= gravity * Time.deltaTime;
charController.Move(moveDirection * (Time.deltaTime * walkSpeed));
}

This doesn't work for a Third Person Controller.