网站开发岗位职责任职责格百度seo和谷歌seo有什么区别
ajax是前端与后端数据库进行交互的最基础的工具，第三方的工具库比如jquery,axios都有对ajax进行第二次的封装，fecth是浏览器原生自带的功能，但是它与ajax还是有区别的，总结如下：
ajax与fetch对比
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实现效果
代码实现
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><script src="./js/ajax.js"></script>
</head>
<body><form action="" method="POST"><input type="text" name="" id="userInput" /> <br><input type="text" name="" id="pwdInput" /> <br><input type="button" value="提交" id="btn"></form><div id="box"></div><script>window.onload = function(){const oBtn = document.querySelector('#btn');const oInput = document.querySelector('#userInput');const oPwd = document.querySelector('#pwdInput');const oBox = document.querySelector('#box');oBtn.onclick = function(){if(oInput.value == ''){alert('请输入内容');}else{http(`http://127.0.0.1:8080/api/user/form`,{name:oInput.value,pwd:oPwd.value},function(data){oBox.innerHTML = `Hello ${data.data.name},欢迎你 ${data.data.pwd}`;},"POST")}}}</script>
</body>
</html>
ajax封装
function http(url, data, cb, method = "GET") {const xhr = getXHR();console.log("🚀 ~ http ~ xhr:", xhr);xhr.open(method, url, true); // true为异步请求,false为同步请求xhr.onreadystatechange = function () {// 状态改变后执行此方法if (xhr.readyState === 4 && xhr.status === 200) {cb(JSON.parse(xhr.responseText)); // 字符创转成json}};xhr.setRequestHeader("Content-Type", "application/json");xhr.responseType = "application/json";xhr.send(method === "GET" ? null : JSON.stringify(data)); // 发送请求数据,GET方法不需要传递数据
}//兼容处理
function getXHR() {let xhr = null;if (window.XMLHttpRequest) {xhr = new XMLHttpRequest();} else {xhr = new ActiveXObject("Microsoft.XMLHTTP");}return xhr;
}
node实现的数据接口
- 配置了跨域及解析前端请求数据的中间件
const express = require("express");
const userRouter = require("./routes/user");
const bodyParser = require("body-parser");
const cors = require("cors");
const app = express();// 允许跨域
app.use(cors());// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: false }));// parse application/json
app.use(bodyParser.json());app.use("/api/user", userRouter);app.listen(8080, () => {console.log("Server is running on port 8080");
});
- 接口数据处理
const express = require("express");const router = express.Router();
// 模拟数据库，也可以介入mysql或者mongodb
const names = ["张三", "李四", "王五", "赵六"];router.get("/", (req, res) => {res.send("Hello World!");
});router.post("/form", (req, res) => {console.log("🚀 ~ router.post ~ req:", req.body);const { name, pwd } = req.body;if (names.includes(name)) {return res.json({code: 1,data: {name: "该用户名已经注册啦",pwd: "",},});} else {return res.json({code: 0,data: {name: `我是服务端返回的数据` + name,pwd: `我是服务端返回的数据` + pwd,},});}
});module.exports = router;
这样，我们就可以实现前后端的数据交互了。