title: How to unset variable using javascript?
body: <p>This is what I tried so far.</p>
  
  <pre><code>var nxt = 'I am next';
  
  window.onscroll = function(){
      var scr = this.pageYOffset;
  
      if(scr &gt; 400){
          console.log(nxt);
          delete(nxt); // unset here
          console.log(nxt); // expected undefined or null
      }
  }
  </code></pre>
  
  <p>I used delete() expecting to remove the reference value inside the variable. Unluckily, it just remain the same. Can somebody give me a clue on how to achieve this kind of scenario? </p>
  
  <p>Any help would be appreciated.</p>