title: Getting a integer value from a textbox, how to check if it's NaN or null etc?
body: <p>I am pulling a value via JavaScript from a textbox. If the textbox is empty, it returns <code>NaN</code>. I want to return an empty string if it's null, empty, etc.</p>
  
  <p>What check do I do? <code>if(NAN = tb.value)</code>?</p>