使用htmlfor获取输入值

<input type="text" id="myInput">
<button onclick="getValue()">获取输入值</button>

<script>
function getValue() {
  var input = document.getElementById("myInput");
  var value = input.value;
  alert("输入值为：" + value);
}
</script>

<select id="mySelect">
  <option value="option1">选项1</option>
  <option value="option2">选项2</option>
  <option value="option3">选项3</option>
</select>
<button onclick="getValue()">获取选中值</button>

<script>
function getValue() {
  var select = document.getElementById("mySelect");
  var value = select.value;
  alert("选中值为：" + value);
}
</script>

<input type="checkbox" id="myCheckbox">
<button onclick="getValue()">获取选中状态</button>

<script>
function getValue() {
  var checkbox = document.getElementById("myCheckbox");
  var checked = checkbox.checked;
  if (checked) {
    alert("复选框已选中");
  } else {
    alert("复选框未选中");
  }
}
</script>