<select id="selectBox">
  <option value="option1">选项1</option>
  <option value="option2">选项2</option>
  <option value="option3">选项3</option>
</select>

<button id="submitButton">提交</button>

<textarea id="textArea"></textarea>

// 获取选择框和提交按钮的引用
var selectBox = document.getElementById("selectBox");
var submitButton = document.getElementById("submitButton");
var textArea = document.getElementById("textArea");

// 添加点击事件监听器
submitButton.addEventListener("click", function() {
  // 获取选择框的选中值
  var selectedValue = selectBox.value;
  
  // 将选中值添加到文本区
  textArea.value += selectedValue + "\n";
});