如何将数据从html发送到节点js？

Question

下面是我的html 代码，我从那里通过 JQuery 发送数据

 <script type="text/javascript">
      $(document).ready(function(){
        sndt();
        function sndt(nid){
        $.ajax({
          url:"localhost:3000/client",
          method:"POST",
          data:{nid,test:"dooo"},
          success:function(data){
              $("#video").html(data);
      },
      error:function(data){
        console.log("ZUBAIR");
      }
        })
      }
      })
</script>

现在我想在我的节点 js 控制台中显示这个测试数据这是我在节点 js 中的代码

require("dotenv").config();
const express = require("express");
const path = require("path");
var cons = require('consolidate'); 
var bodyParser = require('body-parser');
const app = express();
app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  next();
});
app.use(bodyParser.urlencoded({extended:false}));
app.engine('html', cons.swig)
app.set('views', path.join(__dirname, 'www'));
app.set('view engine', 'html');

var PORT = process.env.PORT || 3000; // signalingServerPort
var localHost = "http://localhost:" + PORT; // http
app.use(express.static(path.join(__dirname, "www")));
// Remove trailing slashes in url
app.use(function (req, res, next) {
  if (req.path.substr(-1) === "/" && req.path.length > 1) {
    let query = req.url.slice(req.path.length);
    res.redirect(301, req.path.slice(0, -1) + query);
  } else {
    next();
  }
});
// no room name specified to join
app.get("/join/", function (req, res) {
  res.redirect("/");
});
// join to room
app.post("/join/*", function (req, res) {
  var t = (req.body.test);
  console.log("ttttt"+ t);
  if (Object.keys(req.query).length > 0) {
    console.log("redirect:" + req.url + " to " + url.parse(req.url).pathname);
    res.redirect(url.parse(req.url).pathname);
  } else {
    var t = (req.body.test);
  console.log("ttttt"+ t);
    res.sendFile(path.join(__dirname, "www/client.html"));
  }
});

这些是我面临的错误

Access to XMLHttpRequest at 'localhost:3000/client' from origin 'http://localhost:3000' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, chrome, chrome-extension, chrome-untrusted, https.

和

jquery-2.2.4.js:9175 POST localhost:3000/client net::ERR_FAILED

这是我的节点 js 代码，我哪里出错了？？谢谢？

Answer 1

当你从前端调用到后端时，这是一个 cors 问题，你必须在后端代码中启用 cors

所以你需要先通过运行以下命令来安装cors

npm install cors

安装后进入node js代码并导入cors并使用cors，因为我使用了以下代码

  var cors = require('cors')
        var app = express()
        
        app.use(cors())