title: Can I delete global variables in JavaScript
body: <p>I'd like to delete all global variables that begin with '<strong>Nwxp</strong>'. </p>
  
  <p>Therefore I iterate over all global variables. </p>
  
  <p>Check if the beginning is equal with my string and then delete them. </p>
  
  <p>However, the delete keyword doesn't delete my variables. What am I doing wrong? </p>
  
  <p>Here's my code:</p>
  
  <pre><code>var strNwxp    = "Nwxp";
  
  for (var variable in global){
      var toCheck = variable.substring(0, 4);
      if (strNwxp === toCheck) {
          delete variable;
      }
  }
  </code></pre>