title: Why is "element.innerHTML+=" bad code?
body: <p>I have been told not to append stuff using <code>element.innerHTML += ...</code> like this:</p>
  
  <pre><code>var str = "&lt;div&gt;hello world&lt;/div&gt;";
  var elm = document.getElementById("targetID");
  
  elm.innerHTML += str; //not a good idea?
  </code></pre>
  
  <p>What is wrong with it?, what other alternatives do I have?</p>