title: Why selecting by ID is not recommended in CSS?
body: <p>In <a href="http://csslint.net" rel="noreferrer">CSS Lint</a>, they don't recommend using an <code>id</code> for selecting elements. I trust CSS Lint because it written by smart people who know CSS very good and in depth. But I want to know what are <strong>reasons</strong> of this? Why is selecting with an <code>id</code> not a good thing?</p>