title: Parsing to Check if NAN Javascript
body: <p>I have an onclick even set up to take the value of an input and alert if the value is a number.  If the value of the input is blank, I am trying to alert it to say "No Number," however, it seems that even if my input it empty the function returns a statement saying the the "empty" value is indeed a number.</p>
  
  <p>I have set variable up to parse the value of the input right away, but is this why my code is always returning "Is a number," because it's automatically set to be one when it collects the variable?</p>
  
  <p>Code:</p>
  
  <p>HTML:</p>
  
  <pre><code>&lt;input type="text" id="numberTest" /&gt;
  
  &lt;button id="button"&gt;Click Me&lt;/button&gt;
  </code></pre>
  
  <p>JS:</p>
  
  <pre><code>var button = document.getElementById("button");
  
  button.onclick = function()
  {
  var numberTest = parseInt(document.getElementById("numberTest").value);
  
  if(numberTest == NaN || "" || null)
  {
      alert("No Number");
  }
  else
  {
      alert("This is a number!");
  }
  };
  </code></pre>