How to make a save script in javascript.

I've been trying to figure out how to write a proper save/load script using java, but haven't had much luck. It seems PlayerPrefs is a pretty common (and fairly easy) way of going about it, but apparently it isn't that secure. I followed the tutorial here, but I am using javascript in my project. I know it's possible to translate it into javascript as I have read several posts from users saying they have done it, but I haven't been able to find any written script that shows what needs to be changed. I have translated it as far as I can and only have one error appearing now. I'll post my script plus the error below.

 var saveVariable : int;
 public static var control : SaveScript;
 
 function Awake()
 {
     if(control == null)
     {
         DontDestroyOnLoad(transform.gameObject);
         control = this;
     }
     else if(control != this)
     {
         Destroy(gameObject);
     }
 }
 
 public function Save()
 {
     var bf : BinaryFormatter = new BinaryFormatter();
     var file : FileStream = FileCreate(Application.persistentDataPath + "/playerInfo.dat");
     
     var data : PlayerData = new PlayerData();
     data.saveVariable = saveVariable;
     
     bf.Serialize(file, data);
     file.Close();
 }
 
 public static function Load()
 {
     if(File.Exists(Application.persistentDataPath + "/playerInfo.dat"))
     {
         var bf : BinaryFormatter = new BinaryFormatter();
         var file : FileStream = File.Open(Application.persistentDataPath + "/playerInfo.dat", FileMode.Open);

        ////////////////THIS IS THE LINE THE ERROR APPEARS ON/////////////
         var data : PlayerData = (PlayerData)bf.Deserialize(file); 
       //////////////////////////////////////////////////////////////////

         file.Close();
         
         saveVariable = data.saveVariable;
     }
 }
 
 [Serializable];
 public class PlayerData
 {
     public var saveVariable : int;
 }

The error that appears is: Assets/Resources/Scripts/SaveScript.js(43,53): UCE0001: ';' expected. Insert a semicolon at the end.

I know this alone might not fix it, because this may be one of those cases where fixing one error can cause 10 more to appear, but I guess I'm mainly just hoping someone can tell me what I have wrong or point me in the right direction. Thanks for any help!