title: Unable to set property 'innerHTML' of undefined or null reference
body: <p>Get this strange error. I am learning javaScript and copy the code from somewhere and run it but get the error. Here is the code. Change the empty string to any other thing like "Test" I will still get the same error.</p>
  
  <pre><code> &lt;script&gt;
  
      function theAge() {
          var message, x;
          message = document.getElementById("message");
          message.innerHTML = "";
          x = document.getElementById(age).value;
          try {
              x=Number(x);
              if(x=="") throw "is empty";
              if(isNaN(x)) throw "is not a number";
              if(x&gt;10) throw "is too high";
              if(x&lt;5) throw "is too low";
          }
          catch (err) {
              message.innerHTML = "input" + err;
          }
      }
  &lt;/script&gt;
  </code></pre>