Edit in JSFiddle

Result
HTML
JavaScript
CSS

<html>
    <head><title>Article tag in HTML5</title>
    </head>
    <body>
        <article class="article">
            <b>jQuery</b>
            <p>jQuery is a multi-browser JavaScript library designed to simplify the client-side scripting of HTML. It was released in January 2006 at BarCamp NYC by John Resig. </p>
            <p>It is currently developed by a team of developers led by Dave Methvin. Used by over 55% of the 10,000 most visited websites, jQuery is the most popular JavaScript library in use today</p>
        </article>
        <br />
        <button id="myButton">Toggle Class</button>
    </body>
</html>

$(document).ready(function()
                  {
                      $("#myButton").click(function()
                                          {
                                              $("article").toggleClass("article");
                                          });
                  });

.article
            {
                font-family:comic sans ms;
                color:orange;
                border:10px solid skyblue;
            }