What is a framebuster in the context of web development and why is it important to understand when using iframes in PHP?

A framebuster is a piece of code that prevents a webpage from being loaded within an iframe. This is important to understand when using iframes in PHP because it can help protect your website from clickjacking attacks, where malicious websites attempt to trick users into clicking on something different than what they see. To implement a framebuster in PHP, you can include the following code snippet in your PHP file:

<script type="text/javascript">
    if (top != self) {
        top.location.replace(self.location.href);
    }
</script>