<time> for date and time
You use the time element to represent a time of day or a date. The datetime attribute specifies the date or time in a format specified by RFC3339(http://tools.ietf.org/html/rfc3339).
<!DOCTYPE HTML>
<html>
<head>
<title>Example</title>
</head>
<body>
<time datetime="15:00">3 o'clock</time> on <time datetime="2011-12-7">December 7th</time>.
</body>
</html>