的“ OnChange”功能 <html:select> 字段不起作用

Question

我的JavaScript函數無法正常工作。 我的網頁上沒有任何警報消息。 請幫助我... 這是我的HTML代碼

function checkCompletedProjectStatus() {
  alert("Helloo");
  var dropdownType = document.getElementById("status");
  var current_value = dropdownType.options[dropdownType.selectedIndex].value;
  var dropdown = document.getElementById("extendedHours");
  dropdown[1].style.display = "block";
  dropdown[2].style.display = "block";
  dropdown[3].style.display = "block";
  dropdown[4].style.display = "block";
  dropdown[5].style.display = "block";
  dropdown[6].style.display = "block";
  if (current_value == "Completed") {
    alert("Current Value" + current_value);
    dropdown[1].style.display = "none";
    dropdown[2].style.display = "none";
    dropdown[3].style.display = "none";
    dropdown[5].style.display = "none";
  }
}

<html:select name="status" property="theTasks.status" value="theTasks.status" onchange="checkCompletedProjectStatus(this)">
  <option value="">Select Status</option>
  <option value="Scheduled">Scheduled</option>
  <option value="In progress">In progress</option>
  <option value="Completed">Completed</option>
  <option value="On hold">On hold</option>
  <option value="Extended">Extended</option>
</html:select>

Answer 1

以下代碼提示選定的值（我已刪除未使用的代碼）

HTML：

<select id="status" property="theTasks.status" value="theTasks.status" onchange="checkCompletedProjectStatus(this)">
  <option value="">Select Status</option>
  <option value="Scheduled">Scheduled</option>
  <option value="In progress">In progress</option>
  <option value="Completed">Completed</option>
  <option value="On hold">On hold</option>
  <option value="Extended">Extended</option>
<select>

Javascript：

function checkCompletedProjectStatus(target) {
  var dropdownType = document.getElementById("status");
  var current_value = target.value;

  alert('selected value: '+ current_value);

  if (current_value === "Completed") {
    alert("Completed selected");
  }
}