function openChat() {
  for (let i = 0; i < chatId.length; i++) {
    document.getElementById(chatId[i]).classList.add('chatBox');
    document.getElementById(chatId[i]).addEventListener('click', function(){
      if(!document.getElementById('1')){
        let chat = document.createElement('div');
        chat.classList.add('chat');
        chat.id = '1';
        document.body.appendChild(chat);
        let friendName = document.createElement('div');
        friendName.innerHTML += friends[i];
        friendName.classList.add('friendChatName');
        document.getElementById(1).appendChild(friendName);
        let textArea = document.createElement('textarea');
        textArea.classList.add('textArea');
        textArea.placeholder = 'Send a message';
        textArea.onkeypress = 'onKeyDown();';
        document.getElementById(1).appendChild(textArea);
      }else{
        document.getElementById('1').remove();
        let chat = document.createElement('div');
        chat.classList.add('chat');
        chat.id = '1';
        document.body.appendChild(chat);
        let friendName = document.createElement('div');
        friendName.innerHTML += friends[i];
        friendName.classList.add('friendChatName');
        document.getElementById(1).appendChild(friendName);
        let textArea = document.createElement('textarea');
        textArea.classList.add('textArea');
        textArea.placeholder = 'Send a message';
        textArea.onkeypress = 'onKeyDown();';
        document.getElementById(1).appendChild(textArea);
      }
    });
  }
}

test = new openChat();