JSFiddle - React, Tailwind, and code Playground

HTML

<div class="siteads">siteadd
    <!-- js-code goes here -->
</div>
<div id="adblockmessage">addblocker
    <!-- adblock message goes here -->
</div>

JavaScript

function blockAdblockUser() {
    //alert($('.siteads').height());
    if ($('.siteads').height() == 200) {
        $('#adblockmessage').show();
    }
        else $('#adblockmessage').hide();
    
}

$(document).ready(function () {
    blockAdblockUser();
});