This is a classic situation where you could use a number of different paths to attain the same goal, ranging from a CGI solution to a small server-side include, to a PHP script or, the solution I'll demonstrate here, a JavaScript client-side snippet.
Each has its strengths and weaknesses, and for JavaScript the risk is that some percentage of your viewers will probably have JavaScript disabled in their browsers. Assuming you can live with only about 95% of your visitors knowing if you're on the air at that moment, this should work reasonably well, and it's really easy to add without making any changes on the server.
There's one other potential hiccup in that since JavaScript is client-side, and since it's working with time, there's no way for the script to know if the visitor has their computer clock set wrong. Ah well. Let's assume that's not a big crisis either, shall we?
The first part of this script simply grabs the current time of day then extracts the Universal Time Coordinated (UTC, this used to be called Greenwich Mean Time and then Zulu Time) values for day of week and hour of day. Three simple lines:
var thedate = new Date();
var dayofweek = thedate.getUTCDay();
var hourofday = thedate.getUTCHours();
I'll also create a simple function that lets you add conditional HTML content anywhere on the page by simply testing if (onAir()):
function onAir()
{
// return TRUE if it's Mon through Sat, 3a-6a UTC
if (dayofweek != 0 &&
((hourofday > 2 && hourofday < 7))) {
return true;
}
return false;
}
To show how this works, here's an entire HTML page that includes this JavaScript and an example of how to use this new function elsewhere in the page:
<head>
<script type="text/javascript">
var thedate = new Date();
var dayofweek = thedate.getUTCDay();
var hourofday = thedate.getUTCHours();
function onAir()
{
// return TRUE if it's Mon through Sat, 3a-6a UTC
if (dayofweek != 0 &&
((hourofday > 2 && hourofday < 7))) {
return true;
}
return false;
}
</script>
</head><body>
<h1>The David Lawrence Show!</h1>
<script type="text/javascript">
if (onAir()) {
document.write("<h2>ON THE AIR</h2>");
} else {
document.write("<h2>OFF THE AIR</h2>");
}
</script>
<p>
If you want to learn more about David's show,
please visit
<a href="http://thedavidlawrenceshow.com/">The
David Lawrence Show</a>
</p>
</body>
</html>
I'll leave the rest of it in your capable hands, David, and encourage everyone else to pop over to your sites and learn about both of your great radio programs The David Lawrence Show and Online Tonight.
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Dave, how could one accomplish this using PHP?