The easiest way is to use IFTTT. https://ifttt.com
From there use the My Applets Webhooks to connect your website to your Hue Light.
To call IFTTT, you will want to use PHP and cURL. You can technically do a straight up JS GET request, but you'd be giving away your key to the entire Internet, which is not the best idea. You may also need to make sure your server has cURL enabled.
To do this, create a PHP file, and add in the following code, and replace the {{key}} with the key generated in IFTTT, which you can find here: https://ifttt.com/services/maker_webhooks/settings
<?php
header('Access-Control-Allow-Origin: https://maker.ifttt.com');
if(!isset($_GET['triggerLight'])){
die('No URL set');
}
$triggerLight = $_GET['triggerLight'];
$url = 'https://maker.ifttt.com/trigger/' . $triggerLight . '/with/key/{{ACCESS_KEY_FROM_IFTTT}}';
echo($url);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
$output = curl_exec($ch);
echo $output;
curl_close($ch);
?>
Notice the access control header. This is so you won't have to worry about cross site domain. (This PHP file is cobbled together from several Google searches, so it could probably be improved.)
Now using jQuery we'll do an ajax GET request to the PHP file we just created. Feel free to use vanilla JS, if you would like.
$.ajax({
type: 'GET',
url: "PATH_TO/iftt.php?triggerLight={{WEBHOOK_MAKER_EVENT_NAME}}"
});
You can have this run when your home page is loaded, and you should be good to go for what you want to do. There will probably be a rate limit at some point, depending on how heavy the traffic is to your site. There is approximately a 1-2 second delay going through IFTTT, but it's easier than going through the HUE API, mostly because to connect remotely you need to fill out a form to request access to the remote API.
I will say, that you want to be careful with what you wish for, since a blinking light every time a user visits your site might be really annoying for you. I chose a calming candle flame type hue, for an event tracking feature I built. I also chose not to turn the light on and off, up to you however.
Finally, as noted above, try not to ruin us all with this code. :)