BCE0044: expecting ':' found ';'

I'm a student trying to make a 2 player pong game for my final. I have a two scripts for movement and they are both getting the same error at the same place. I don't know how to resolve the error because of my limited knowledge of javascript. Can someone please help?

Below is one of my scripts. The error is after the last parenthesis. It says it expects ':' but i don't know why and when i put one there i just get more errors.

var PlayerSpeed : float;

function Update ()  {
    if (Input.GetButtonDown ("Keycode.W")) or (Input.GetButtonDown ("Keycode.S"));{
        transform.Translate(Input.GetAxisRaw("Horizontal") * Time.deltaTime * PlayerSpeed, 0, Input.GetAxisRaw("Vertical") * Time.deltaTime * PlayerSpeed);
    }
}

You should learn the basics of coding, i've changed your code: (Didnt test). Use || instead or OR in an if statement. Also, make sure you end your if statement with an ).

var PlayerSpeed : float;

function Update () { 
    if (Input.GetButtonDown ("Keycode.W") || Input.GetButtonDown ("Keycode.S")) { 
        transform.Translate(Input.GetAxisRaw("Horizontal") * Time.deltaTime * PlayerSpeed, 0, Input.GetAxisRaw("Vertical") * Time.deltaTime * PlayerSpeed); 
    } 
}