title: how to change <meter> values?
body: <p>I'm a beginner at HTML, and while learning about HTML5 I've found a cool tool, the <code>&lt;meter&gt;</code>. However, it won't update; it's there as a static value!</p>
  
  <p>My question is simple: how do I use the length of a <code>&lt;textarea&gt;</code> to change the color of <code>&lt;meter&gt;</code>, so that the user will, for example, see red when he reaches 160 characters (the maximum value)?  In other words, count the <code>&lt;textarea&gt;</code> characters, and send them to the value of the meter tag.</p>