模板字符串在下拉框里面的应用```js ``` 用let定义一个变量，用let定义一个变量，用let定义一个变量，

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>Document</title>
  </head>

  <body>
    <select id="province"></select>
    <script>
      let provinces = [
        "北京市",
        "天津市",
        "上海市",
        "重庆市",
        "河北省",
        "山西省",
        "辽宁省",
        "吉林省",
        "黑龙江省",
        "江苏省",
        "浙江省",
        "安徽省",
        "福建省",
        "江西省",
        "山东省",
        "河南省",
        "湖北省",
        "湖南省",
        "广东省",
        "海南省",
        "四川省",
        "贵州省",
        "云南省",
        "陕西省",
        "甘肃省",
        "青海省",
        "台湾省",
        "内蒙古自治区",
        "广西壮族自治区",
        "西藏自治区",
        "宁夏回族自治区",
        "新疆维吾尔自治区",
        "香港特别行政区",
        "澳门特别行政区",
      ];
      //   用let定义一个变量，
      let optionString = "";
      let selectObj = document.getElementById("province");
      for (let index = 0; index < provinces.length; index++) {
        const element = provinces[index];

        optionString += `  <option value="${element}">${element}</option>`;
      }
      selectObj.innerHTML = optionString;
    </script>
  </body>
</html>