title: Event for textarea changes
body: <p>I have a JavaScript library that updates a <strong>hidden</strong> <code>&lt;textarea&gt;</code> HTML element with some data based on some things.</p>
  
  <p>In my (JavaScript) application I'd like to know when these updates occur without having to go through the existing library code.</p>
  
  <p>I was hoping there was an event for this, but apparently not.</p>
  
  <p>How would I listen for changes of the textarea?</p>
  
  <p>Changes can be as simple as <code>document.getElementById("myTextarea").value = "hello";</code></p>
  
  <p><strong>EDIT</strong> I will be using FireFox only, since this code will only be part of a <em>test suite</em> I'm building.</p>