Show different CSS styles to the site in a time period

The above two sites is based on the time to automatically adjust the site style, in fact, the time to automatically adjust the site style is not a new thing, remember a long time ago have seen similar articles or methods, but did not pay special attention.
Okay, here's how they're implemented, and there are two ways to do it online.
1) using the service-side code
ASP version:
<link rel= "stylesheet" type= "Text/css"
<%
If hour (now) <12 then
Response.Write "Morning.css"
ElseIf Hour (now) <17 then
Response.Write "Day.css"
Else
Response.Write "Night.css"
End If
%>
"/>

PHP Version:
<link rel= "stylesheet" type= "Text/css"
<?php
$hour = Date ("H");
if ($hour < 12)
Echo ' Morning.css ';
else if ($hour < 17)
Echo ' Day.css ';
Else
Echo ' Night.css ';
?>
"/>

2 using JavaScript code
<script type= "Text/javascript" >
<!--
function Getcss () {
Datetoday = new Date ();
Timenow=datetoday.gettime ();
Datetoday.settime (TimeNow);
Thehour = Datetoday.gethours ();
if (thehour<12)
display = "Morning.css";
else if (thehour<17)
display = "Day.css";
Else
display = "Night.css";
（... Want to add more can be ... ）

var css = ' < ';
css+= ' link rel= ' stylesheet ' href= ' +display+ ' \/';
css+= ' > ';
document.write (CSS);
}
-->
</script>
Given that the client may not support or disallow JavaScript, you need to set a default CSS