var dance = $('#dance');
var school = $('#school');
var box = $('.shedule-item');
$('#dance, #school').change(function() {
box.hide().filter(function() {
return $(this).data('dance') == dance.find('option:selected').data('dance') && $(this).data('school') == school.find('option:selected').data('school')
}).show();
});
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
.hidden {
display: none;
}
</style>
<script>
window.onload = function () {
var foo = document.querySelector(".shedule-items");
var message = foo.innerHTML;
var oops = document.querySelector(".oops");
if(message) {
oops.classList.toggle("hidden");
}
}
</script>
</head>
<body>
<div class="shedule-items"></div>
<div class="oops">oops!</div>
</body>
</html><script>
$(document).ready(function() {
var foo = $(".shedule-items");
var message = foo.html();
var oops = $(".oops");
if(message) {
oops.toggleClass("hidden");
}
});
</script>