使用不带jQuery的JavaScript从多个不同的选定下拉列表项中获取值

var dropdown1 = document.getElementById("dropdown1");
var dropdown2 = document.getElementById("dropdown2");
// 依此类推，获取其他下拉列表的引用

<select id="dropdown1">
  <option value="value1">选项1</option>
  <option value="value2">选项2</option>
  <option value="value3">选项3</option>
</select>

<select id="dropdown2">
  <option value="value4">选项4</option>
  <option value="value5">选项5</option>
  <option value="value6">选项6</option>
</select>

<button onclick="getSelectedValues()">获取选定项的值</button>

<script>
function getSelectedValues() {
  var dropdown1 = document.getElementById("dropdown1");
  var dropdown2 = document.getElementById("dropdown2");
  
  var selectedValue1 = dropdown1.value;
  var selectedValue2 = dropdown2.value;
  
  console.log("选定项1的值：" + selectedValue1);
  console.log("选定项2的值：" + selectedValue2);
}
</script>