How to highlight specific values on a page?

For example, on a site like this

How can I code something that will highlight any prices above €20 red within the product grid? Also, I need it to continue to work even when users select/deselect categories on the right.

Would this be JavaScript?

$('div').each(function() {
  $(this).find('.mErEH _223RA').sort(function(a, b) {
    return b.innerText - a.innerText;
  }).slice(0, 5).addClass('higherthan20')
});

.higherthan20 {
  color: red;
}