rtmsendrecv.js

//send messages
sendbtn.addEventListener("click", ()=>{
  channel.sendMessage({ text: msg.value }).then(() => {
    /* Your code for handling events, such as a channel message-send success. */
    chatbox.innerHTML += "<div class='message_holder'><span class='chat user1'>"+ msg.value + "</span></div>";
    console.log("Successfully sent message!");
  }).catch(error => {
    /* Your code for handling events, such as a channel message-send failure. */
    console.log("Error sending message!");
    });
})



if(flag == true){
//receive channel messages
channel.on('ChannelMessage', ({ text }, senderId) => { // text: text of the received channel message; senderId: user ID of the sender.
  /* Your code for handling events, such as receiving a channel message. */
  chatbox.innerHTML +="<div class='message_holder'><span class='chat user2'>"+ text + "</span></div>";
  msg.value="";
});
}