You're checking for the value of the search box on page load, so the searchValue variable is always going to be empty. What you need to do is get the value when the input changes. You can do this with a keyup function. This should get you started:
$(function() { $('.search-query').keyup(function() { var searchValue = $(".search-query").val(); $( ".searchResults-description:contains('" + searchValue + "')").css("background-color", "#fadcd9" ); }); });<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <input class="search-query" /> <div class="searchResults-description">Lorem</div> <div class="searchResults-description">Ipsum</div>