Mouse cursor - Please Help

Hi,
i have problem with mouse cursor, it is invisible in start, and i want that it appears when i press ecs button, i made this script :

static var showCursor :bool ;
function Start () {
Screen.showCursor = false;
}

function Update () {
if( Input.GetKey(KeyCode.Escape));
Screen.showCursor = true;
}

but is showing me this error:
Assets/Player.js(2,25): BCE0018: The name ‘bool’ does not denote a valid type (‘not found’).

Can anybody help me?

static var showCursor :bool ;

get rid of that line.

var showCursor :boolean;
function Start () {
Screen.showCursor = false;
}

function Update () {
if( Input.GetKey(KeyCode.Escape));
Screen.showCursor = true;
}

Hi try this

#pragma strict //Add this very Important

public var ShowCursor:boolean = false; // <-- See changes i made cahnged from bool(C# syntax) to boolean(JS syntax)


function Start () {
Screen.showCursor = false;
Screen.lockCursor = true; 
}

function Update () {
if( Input.GetKeyDown(KeyCode.Escape))// <-- Dont add ; at end of an if statement
{
ShowCursor = !ShowCursor;//Toggle   
}
Screen.showCursor = ShowCursor;
Screen.lockCursor = !ShowCursor;///set lock to false when mouse cursor enaled and vice versa
}