When most web sites are launched, they have only a few pages, and if they use includes, normally only have one footer file. It is quite easy to simply hard code the current year in the footer. However, as web sites grow larger, the maintenance can become more difficult if the copyright has been hard coded in every page or if more than one footer becomes necessary (for example if a web site uses multiple designs for different sections of the site or if different sections are written in different languages).
Rather than hard coding the year, it may be more efficient to dynamically generate the year in each footer. Below I have example snippets showing how this can be done in a few different languages. Feel free to add your own suggestions.
PHP
© <? print date("Y"); ?>
ColdFusion
© <cfoutput>#dateFormat(Now(), "yyyy")#</cfoutput>
JSP
<%@ page language="java" contentType="text/html" session="true" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<jsp:useBean id="now" class="java.util.Date" />
...
© <fmt:formatDate value="${now}" pattern="yyyy" />
JavaScript
The following code can be used in static HTML pages or in place of any of the above. It requires no server side work, but it does mean that the browsing client must have JavaScript enabled.
© <script type="text/javascript">
d=new Date();document.write(d.getFullYear());
</script>