CSS3 transitions are effects that are used to change from one style to another. It specify two things:First the CSS property which we want to add an effect to
Second the duration of effect.
<html>
<head>
<style type="text/css">
div
{
width:100px;
height:100px;
background:red;
transition:width 2s;
-moz-transition:width 2s; /* Firefox 4 */
-webkit-transition:width 2s; /* Safari and Chrome */
}
div:hover
{
width:300px;
background:pink;
}
</style>
</head>
<body>
<div></div>
</body>
</html>