百度搜索跨域後得到

app.all('*', function(req, res, next) {

  res.header("Access-Control-Allow-Origin", "*");

  res.header("Access-Control-Allow-Headers", "X-Requested-With");

  res.header("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");

  res.header("X-Powered-By",' 3.2.1')

  res.header("Content-Type", "application/json;charset=utf-8");

  next();

});

雖然 我初學目前看不懂寫的什麼，但是經過測試就是這個跨域設定，導致接收的html檔案被pre標籤包裹。

app.all('*', function(req, res, next) {

  res.header("Access-Control-Allow-Credentials","true");

  res.header("Access-Control-Allow-Origin", "*");

  res.header("Access-Control-Allow-Methods","PUT,GET,POST,DELETE,OPTIONS");

  res.header("ACCess-Control-Allow-Headers","Content-Type,username");

  next();

});

更改，再次讀取頁面，成功返回html。