seperated script to dedicated js file

public/js/script.js

+const socket = io()
+socket.on('message', (msg) => {
+    let messages = document.getElementById("chat-box")
+    let li = document.createElement('li')
+    li.textContent = msg
+    messages.appendChild(li)
+    messages.scrollTop = messages.scrollHeight
+});
+
+function publish(e){
+    let msg = document.getElementById("message").value
+    if(!validate(msg)){
+        return
+    }
+    document.getElementById("message").value = ""
+    socket.emit('message', msg)
+}
+
+function validate(msg){
+    return msg.length > 0 && msg.length <= 140
+}
+
+
+window.onload = () => {
+    document.getElementById('submit').addEventListener('click', e => {
+        e.preventDefault() // stop the submit button from doing itä's usual thing
+        publish()
+    })
+}
\ No newline at end of file