addClass & removeClass

by sum1

HTML

<script src="https://code.jquery.com/jquery-1.10.2.js"></script>
<p class="highlight">Hello</p>
<p>and</p>
<p>Goodbye</p>

<ul>
  <li>sum1</li>
  <li>sum2</li>
  <li>sum3</li>
  <li>sum4</li>
</ul>

CSS

p {
    margin: 8px;
    font-size: 16px;
  }
  .selected {
    color: blue;
  }
  .highlight {
    background: yellow;
  }

JavaScript

$( "p" ).first().removeClass("highlight").addClass( "selected" );
$("ul li").addClass(" selected ");
$("p:last").addClass("highlight");