How can PHP developers ensure that nested textareas do not disrupt the page layout or functionality of a website?

Nested textareas can disrupt the page layout or functionality of a website if not properly handled. To prevent this issue, PHP developers can use CSS to style the textareas and ensure they do not overlap or interfere with other elements on the page. Additionally, developers can use JavaScript to dynamically adjust the size of the textareas based on user input or content length.

```php
<textarea name="parent_textarea" id="parent_textarea"></textarea>
<div class="nested_textarea_container">
    <textarea name="nested_textarea" id="nested_textarea"></textarea>
</div>
```

In the above code snippet, we have a parent textarea and a nested textarea within a container. By styling the nested_textarea_container with CSS to ensure proper spacing and sizing, we can prevent any disruption to the page layout. Additionally, JavaScript can be used to dynamically adjust the size of the nested textarea based on user input or content length, further ensuring a smooth user experience.