Automatical "control key + F" without pressing when page is loading

The code below is usual php code for hilighting with “search.php?key=book”

str_replace($_GET['key'], '<b>'.$_GET['key'].'</b>', $text_in_the_page_of_search);

Instead of the code above, I like to make it like the following.

Can I make the page working like the above with your help?

I am not sure this topic should go to javascript or stay in php.

Your webpage cannot push buttons in the browser.

It is a massive security violation.

2 Likes might be a nice client side alternative to highlight search words in the page.