gihyo-dl.html

<script src="https://unpkg.com/axios/dist/axios.min.js"></script>
<script>
  axios.defaults.headers['x-requested-with'] = 'XMLHttpRequest';
  
  function getURLFromHTML(html){
    return new DOMParser().parseFromString(html, "text/html").querySelector('a').href;
  }
  
  function getURLById(param, type){
    return new Promise((resolve, reject) => {
      axios.get('/dp/api/v2/function', {params: {url: 'download', param, isLogin: true}});
      var intervalID = setInterval(async () => {
        var response = await axios.get('/dp/api/v2/function', {params: {url: 'dlmakecheck', param, isLogin: true, acTime: new Date().getTime()}});
        if(response.data.finish){
          clearInterval(intervalID);
          var url = null;
          response.data.item.forEach(item => {
            if(item.clsname.startsWith(type))
              url = getURLFromHTML(item.html);
          });
          resolve(url);
        }
      }, 1000);
    });
  }
</script>