What is the best practice for handling popup windows in PHP applications?

When handling popup windows in PHP applications, it is best practice to use JavaScript to control the popup behavior. This allows for better control over the popup window's size, position, and other properties. By using JavaScript, you can also ensure that the popup window is displayed correctly across different browsers.

// PHP code to create a popup window using JavaScript
echo '<script type="text/javascript">';
echo 'window.open("popup.html", "Popup", "width=400,height=400");';
echo '</script>';