Error in my Greade script.

I started my grenade script when i got these errors. Assets/scripts/Grenade.js(18.27)BCE0044:expecting ), found '=' Assets/scripts/Grenade.js(18.29)BCE0043:unexpected token: false Assets/scripts/Grenade.js(21.27)BCE0044:expecting :, found '='

I guess they have to do something with {

} here is my code:

 var grenadeActive : boolean = false;
 
 function Start () {
 
 }
 
 function Update () 
 {
     if (Input.GetKey(KeyCode.G))
         
         Grenade();
 }
 
 function Grenade(){
     
     if (grenadeActive = false)
     {
     
     gameObject.active = true;
     grenadeActive = true;
     
     } else {
     
     gameObject.active = false;
     grenadeActive = false;
 }
 }

can someone please help me? if you need more information say it please.