Node is a skill that must be learned in the front-end. We all know that node uses js as the back-end. Before learning node, we need to understand how node realizes front-end and back-end interaction. This article brings you a simple front-end and back-end interaction of Node (explanation with examples). The editor thinks it is quite good, so I will share it with you now and give it as a reference for everyone. Let’s follow the editor to take a look, I hope it can help everyone.

Here is a simple interaction between native ajax and node. Friends who have just learned node can take a look. On the one hand, you understand how the server and client interact, and on the other hand, you are more familiar with node development.

Post the code first: (If you are interested, you can copy it locally and run it yourself)

The html of the main page

index.html:

     
  food other 
   

Next is the server-side code. The running method is to enter the command in the node environment: node server.js

server.js:

let http = require('http'); let qs = require('querystring'); let server = http.createServer(function(req, res) { let body = ''; // 一定要初始化为"" 不然是undefined req.on('data', function(data) { body += data; // 所接受的Json数据 }); req.on('end', function() { res.writeHead(200, { // 响应状态 "Content-Type": "text/plain", // 响应数据类型 'Access-Control-Allow-Origin': '*' // 允许任何一个域名访问 }); if(qs.parse(body).name == 'food') { res.write('apple'); } else { res.write('other'); } res.end(); }); }); server.listen(3000);

The qs module introduced is used to parse JSON

req.on('data', callback); // Monitor the client's data and execute the callback function once data is sent

req.on('end', callback); // Data reception completed

res //Response

Client js (the function is responsible for some DOM operations and sending ajax requests)

client.js:

let btn1 = document.getElementById('btn1'); let btn2 = document.getElementById('btn2'); let content = document.getElementById('content'); btn1.addEventListener('click', function() { ajax('POST', "http://127.0.0.1:3000/", 'name='+this.innerHTML); }); btn2.addEventListener('click', function() { ajax('POST', "http://127.0.0.1:3000/", 'name='+this.innerHTML); }); // 封装的ajax方法 function ajax(method, url, val) { // 方法，路径，传送数据 let xhr = new XMLHttpRequest(); xhr.onreadystatechange = function() { if(xhr.readyState == 4) { if(xhr.status >= 200 && xhr.status < 300 || xhr.status == 304) { content.innerHTML = xhr.responseText; } else { alert('Request was unsuccessful: ' + xhr.status); } } }; xhr.open(method, url, true); if(val) xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded'); xhr.send(val); }

This simple interaction is like this. In fact, when we first learn a back-end language, the first thing we do is to write a front-end and back-end interactive program. This will help us better understand the division of labor between the front and back ends.

run method:

First run server.js, and then open html to request a response.

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