JavaScript动态添加表单字段技巧

// HTML 中的 select 元素
<select id="mySelect">
  <option value="">请选择一项</option>
&lt;/select&gt;

// JavaScript 动态添加选项
const select = document.getElementById("mySelect");
const newOption = document.createElement("option");
newOption.value = "value1";
newOption.text = "选项一";
select.appendChild(newOption);

const select = document.getElementById("mySelect");
const option = new Option("选项二", "value2"); // text, value
select.add(option);

const select = document.getElementById("mySelect");
const optionsData = [
  { text: "北京", value: "beijing" },
  { text: "上海", value: "shanghai" },
  { text: "广州", value: "guangzhou" }
];

optionsData.forEach(item => {
  const option = new Option(item.text, item.value);
  select.add(option);
});

function addUniqueOption(selectId, text, value) {
  const select = document.getElementById(selectId);
  for (let i = 0; i