title: Eclipse HTML: placeholder is not an attribute?
body: <p>I am using the latest version of Eclipse Luna (for Java EE developers), and when I insert an <code>&lt;input type='text' placeholder='test123'</code>, eclipse says "Undefined attribute name (placeholder).".</p>
  
  <p><img src="https://i.stack.imgur.com/twXKZ.png" alt="enter image description here">
  Why is it like that? Have I done something wrong? Is there a way of fixing this?</p>