HTML <select> JQuery .change not working

I have tried your code in jsFiffle. I manually added some years as options. It works right.

Just bind the .change event in the $(document).ready:

$(document).ready(function(){
  $("#yearDropdown").change(function () {
      alert('The option with value ' + $(this).val());
  });​
});

That code is syntactically correct. Most likely running it at the wrong time.

You'll want to bind the event when the DOM is ready:

---

Native JS/DOM

window.addEventListener('DOMContentLoaded', () => {
    const yearDropDown = document.getElementById('yearDropdown');
    yearDropDown.addEventListener('change', () => { 
        alert(yearDropDown.value)
    });
});

---

jQuery

$(function(){ /* DOM ready */
    $("#yearDropdown").change(function() {
        alert('The option with value ' + $(this).val());
    });
});

Or, use live:

$("#yearDropdown").live('change', function() {
    alert('The option with value ' + $(this).val());
});

Or, use delegate:

$(document.body).delegate('#yearDropdown', 'change', function() {
    alert('The option with value ' + $(this).val());
});

Or, if you're using jQuery 1.7+:

$("#yearDropdown").on('change', function() {
    alert('The option with value ' + $(this).val());
});

---

Nonetheless, it is usually best to execute script once the browser has finished rendering Markup.