Sometimes, comments or posts in your website might be large enough to occupy almost over a web page to display, this could lead the web page to be biased and unbalanced. So, you need alternative presentation to confine those comments.
Here I introduce is an approach that use DIV to limit the maximum height and let it scrollable if necessary.
In HTML, enclose the comment in a <div>.
In CSS, add max-height and overflow-y in the target directive.
border: 1px solid silver;
Scrollable Block Example
Let's see the live output.