javascrpit ischasing error

Me and my friend are creating a zombie game and arent experienced scripters for java. We know Lua pretty well. We are trying to use a sphere as a reference point so that the zombie will start chasing the first person character. We got some help earlier on, and when we put the script in monodevelopment, it says…

assets/aggro detector.js(5,5): BCE0043: Unexpected token: (.

Here is the script we used…

var zombiesSpeed : float = 2.5;

// we can adjust his speed later to fit the game's needs.

var isChasing : boolean = false;

animation["Walk"].wrapMode = WrapMode.Loop;
function OnCollisionEnter(){
isChasing = true;
animation.play ("Walk");
}

function OnCollisionExit(){
isChasing = false;
animation.stop;
}

function Update(){
if isChasing = true {
transform.translate (zombiesSpeed,0,0);
    }
}

Can you either tell us how to fix the script or give us a new one. Thank you for your time.

Your actual error is animation.play("Walk"); instead that animation.Play("Walk");