ERR_ABORTED 404 socket.io (Not Found)

Question

I was trying to program a system that calculates the CPU speed with javascript but I keep on running into socket script source not defined and io is not defined on my console the exact error is /socket.io/socket.io.js ERR_ABORTED 404 (Not Found) . Do you have any idea what might be causing this issue? I double-checked if the src for socket changed at their documentation but no I have the right src I have also tried using <script src="https://cdn.socket.io/3.1.3/socket.io.min.js" integrity="sha384-cPwlPLvBTa3sKAgddT6krw0cJat7egBga3DJepJyrLl4Q9/5WLra3rrnMcyTyOnh" crossorigin="anonymous"></script> instead but that did not solve the issue. Both my HTML and javascript code are attached below. Thanks in advance.

Html

<script src="/socket.io/socket.io.js"></script>
<script> 
var socket = io();
</script>

Javascript

var app = require('express')();
var http = require('http').Server(app);

var io = require('socket.io')(http);

var os = require('os-utils');


app.use(express.static('temp.html'));

var cpuHistogram = [];
var histogramLengtn = 61;
var interval = 100;


http.listen(80, function() {

    console.log('listening on localhost')

    for(var i = 0; 1 < histogramLenth; i++){
        cpuHistogram[i] = [i, 0];
    }

    setInterval(function() {

        os.cpuUsage(function(value){
            io.emit('cpu histogram', value);
        });
    }, interval);

});

Answer 1

declare io like below

var io = require("socket.io").listen(server);

try something like these if you use nginx

    location /socket.io/ {
        
        proxy_pass https://{ip}:{port};


        }