Question

我在这做错了什么？

＆＃13;

var el = document.getElementById('option');
el.addEventListener('change', function() {
  room()
}, false);
var roomOption = el.options[el.selectedIndex].value;

＆＃13;

<select id="option">
  <option value = "1">Option 1</option>
  <option value = "2">Option 2</option>
  <option value = "3">Option 3</option>
  <option value = "4">Option 4</option>
  <option value = "5">Option 5</option>
</select>

＆＃13;

Answer 1

您只需要创建＆＃34;房间＆＃34;功能，您的代码将作为代码段工作。

＆＃13;

var el = document.getElementById('option');
el.addEventListener('change', function() {
  room()
}, false);
//var roomOption= el.options[el.selectedIndex].value;

function room() {
  var roomOption = el.options[el.selectedIndex].value;
  console.log(roomOption);
}

＆＃13;

<select id="option">
            <option value = "1">Option 1</option>
            <option value = "2">Option 2</option>
            <option value = "3">Option 3</option>
            <option value = "4">Option 4</option>
            <option value = "5">Option 5</option>
 </select>

＆＃13;

Answer 2

您的房间功能未定义。从房间内的functoin中选择值

＆＃13;

var el = document.getElementById('option');
el.addEventListener('change', function() {
  room()
}, false);
function room(){
var roomOption = el.options[el.selectedIndex].value;
console.log(roomOption)
}

＆＃13;

<select id="option">
            <option value = "1">Option 1</option>
            <option value = "2">Option 2</option>
            <option value = "3">Option 3</option>
            <option value = "4">Option 4</option>
            <option value = "5">Option 5</option>
        </select>

＆＃13;

Answer 3

在事件处理程序中执行此操作

el.addEventListener('change', function(evt){ 
    var e = evt.target
    var id = e[e.selectedIndex].value; // now use it as you like...
    room(id);    //invoke room with id
}, false)

使用js从下拉列表中获取选定的值

3 个答案: