Display “search again” when the result is empty using JavaScript

I created a dropdown menu filter using JavaScript. I want to display “Search Again” when the result is empty. i.e. if the return result is “null”, write.document(“search again”). I appreciate you taking time to help me!

< script >
$("select.grade, select.type, select.subject").change(update);

function update() {

var resourceGrade = $('select.grade').val();
var resourceType = $('select.type').val();
var resourceSubject = $('select.subject').val();

    $('.property-load-section')

    .find('.property-item')
    .hide()
    .filter(function() {

      var okResourceGrade = true;
      if (resourceGrade !== "all") {
        okResourceGrade = $(this).attr('data-grade') === resourceGrade;
      }
      
      var okResourceType = true;
      if (resourceType !== "all") {
        okResourceType = $(this).attr('data-type') === resourceType;
      }
      
      var okResourceSubject = true;
      if (resourceSubject !== "all") {
        okResourceSubject = $(this).attr('data-subject') === resourceSubject;
      }
      
      console.log(okResourceSubject);
      
      return okResourceGrade && okResourceType && okResourceSubject;
      
    })
    
    .fadeIn('fast');

}
< /script>