title: Is hiding code inside null like this safe?
body: <p>Can you get the key after it's injected?</p>
  
  <pre><code>var outside=[];
  
  var NULL=(function(){
      var key='';
      console.log("Hi, I'm null!");
      window.injectkey=function(k){
          window.injectkey=null;
          key=k;
          return;
          };
      window.askmeforkey=function(){return "nope! I could use my key for stuff though...";}
      setTimeout(function(){
          outside.push("I still exist and can alter things outside but you can't see me!");
          console.log(outside);
          },1000);
      })();
  NULL=null;
  console.log('NULL=='+NULL); // prints NULL==null
  </code></pre>
  
  <p>After try</p>
  
  <pre><code>console.dir(NULL); // prints null
  
  injectkey('xyz');
  </code></pre>
  
  <p>And again</p>
  
  <pre><code>injectkey('abc'); // Uncaught TypeError: injectkey is not a function(…)
  
  askmeforkey() // nope
  </code></pre>
  
  <p><strong>Possible use:</strong> (Say the key might be an encryption key thats not hard coded anywhere)</p>
  
  <p><code>injectkey</code> could be done many ways via some secure encrypted messaging</p>