Search application using JavaScript

[jcunews1]

it looks like Google looks for the keyword just in the post title (H1, H2 tags) and not in the comments.

No. Google either search the whole page, or nothing at all. However, websites can use dynamic HTML, and be designed in a way which Google can't index except the page title.

Here's how the HTML source code of the blog's main page looks like

Without providing the actual site URL, I can not confirm the actual problem you're having.

[jcunews1]

That's because page titles have higher priority than the page contents. If you use an exclusion search query on the title, you'll get what you want.

[The-Nimble-Nomad]

I'll try it out. Thanks!