What are the key differences between HTML and PHP in terms of integrating elements like a SMS ticker?

When integrating elements like a SMS ticker, the key difference between HTML and PHP is that HTML is a markup language used for creating the structure of a webpage, while PHP is a server-side scripting language used for generating dynamic content. To implement a SMS ticker using PHP, you would need to use PHP to fetch the SMS messages from a database or external source and then dynamically display them on the webpage.

<?php
// Connect to database or external source to fetch SMS messages
$messages = array("Message 1", "Message 2", "Message 3");

// Display SMS messages in a ticker format
echo '<marquee direction="left">';
foreach($messages as $message){
    echo $message . ' | ';
}
echo '</marquee>';
?>