Edit in JSFiddle

	<h2>Prettifying the 'title' attribute without Javascript!</h2>

	<p>You can use this for lots of different purposes. You can display links like this, for example <a class="dfn-hover" href="http://www.guuslieben.nl/"><dfn data-info="http://www.guuslieben.nl/">My Website!</dfn></a>, Give information about something: <dfn data-info="JavaScript is the programming language of HTML and the Web.">Javascript</dfn> and who knows what else! You can make text as long or short as you want! Example: <dfn data-info="HTML5 is a core technology markup language of the Internet used for structuring and presenting content for the World Wide Web.">About HTML5</dfn>.</p>
  
	  <p>You can make your page more compact by <i>hiding</i> the information with the data info. Are you ready for it? Follow <a href="http://guuslieben.nl/uploads/hover-info.zip" download>the link</a> to download.</p>

@import url(http://fonts.googleapis.com/css?family=Open+Sans:700,400,300);

::-moz-selection { background: rgba(0,0,0,0.2); }
::selection { background: rgba(0,0,0,0.2); }

/* Skip to line 40 for the hover code */

body {
  background: #fff;
  background-size: 100%;
  font-family: 'Open Sans', sans-serif;
  font-size: 16px;
  line-height: 1.5em;
  margin: 20px 4em 0;
  color: #333;
}
h1 {
  max-width: 49rem;
  font-size: 3.5em;
  line-height: 1em;
  font-weight: 700;
  margin: 0.25em auto;
}
h2 {
  max-width: 49rem;
  margin: 1.4em auto;
}
p {
  line-height: 1.5em;
  margin: 1.4em auto;
  max-width: 49rem;
  font-size: 1em;
  font-weight: 300;
}
a.dfn-hover {
	color: #333;
	text-decoration: none;
}

/** Code for hover info **/

dfn {
  background: #e9e9e9;
  border-bottom: dashed 1px rgba(0,0,0,0.8);
  padding: 0 0.4em;
  cursor: help;
  font-style: normal;
  position: relative;
  
}
dfn::after {
  content: attr(data-info);
  display: inline;
  position: absolute;
  top: 22px; left: 0;
  opacity: 0;
  width: 230px;
  font-size: 13px;
  font-weight: 700;
  line-height: 1.5em;
  padding: 0.5em 0.8em;
  background: rgba(0,0,0,0.8);
  color: #fff;
  pointer-events: none; /* This prevents the box from apearing when hovered. */
  transition: opacity 250ms, top 250ms;
}
dfn::before {
  content: '';
  display: block;
  position: absolute;
  top: 12px; left: 20px;
  opacity: 0;
  width: 0; height: 0;
  border: solid transparent 5px;
  border-bottom-color: rgba(0,0,0,0.8);
  transition: opacity 250ms, top 250ms;
}
dfn:hover {z-index: 2;} /* Keeps the info boxes on top of other elements */
dfn:hover::after,
dfn:hover::before {opacity: 1;}
dfn:hover::after {top: 30px;}
dfn:hover::before {top: 20px;}