根据Dropdownlist SelectionIndexChanged事件更改页面的URL

<select id="myDropdown" onchange="changeURL()">
  <option value="page1.html">Page 1</option>
  <option value="page2.html">Page 2</option>
  <option value="page3.html">Page 3</option>
</select>

function changeURL() {
  var dropdown = document.getElementById("myDropdown");
  var selectedValue = dropdown.options[dropdown.selectedIndex].value;
  window.location.href = selectedValue;
}

function changeURL() {
  var dropdown = document.getElementById("myDropdown");
  var selectedValue = dropdown.options[dropdown.selectedIndex].value;
  var newURL = "https://example.com/" + selectedValue;
  window.location.href = newURL;
}