What are the differences between setting the value of a textarea using PHP directly and using JavaScript functions?

When setting the value of a textarea using PHP directly, the value is set on the server-side and will be rendered in the HTML when the page is loaded. On the other hand, using JavaScript functions to set the value of a textarea allows for dynamic updates on the client-side without requiring a page reload. PHP code snippet:

<textarea><?php echo $textareaValue; ?></textarea>