Adds persistent user notes to Stack Overflow chat

usernotes.user.js

// ==UserScript==
// @name        User Notes (SO Chat)
// @namespace   .
// @include     http://chat.stackoverflow.com/rooms/*
// @include     https://chat.stackoverflow.com/rooms/*
// @version     2
// @grant    GM_getValue
// @grant    GM_setValue
// ==/UserScript==

function makeArea(user_id){
    try{
        var data = GM_getValue(user_id, "(No notes)");

        var container = document.createElement("span");
        container.className = "userscript_added usernotes";

        var textContainer = document.createElement("span");
        textContainer.innerHTML = data.replace("\n", "<br/>");
        container.appendChild(textContainer);

        var textEditor = document.createElement("textarea");
        container.appendChild(textEditor);

        container.appendChild(document.createElement("br"));

        var editButton = document.createElement("a");
        editButton.innerHTML = "(edit)";
        container.appendChild(editButton);

        var saveButton = document.createElement("a");
        saveButton.innerHTML = "(save)";
        container.appendChild(saveButton);

        var discardButton = document.createElement("a");
        discardButton.innerHTML = "(discard)";
        container.appendChild(discardButton);

        function setMode(mode){
            if(mode == "view"){
                var viewStyle = "inline";
                var editStyle = "none";
            }
            else if(mode == "edit"){
                var viewStyle = "none";
                var editStyle = "inline";      
            }
            else{
                console.log("Unrecognized mode " + mode);
            }
            textContainer.style.display = viewStyle;
            editButton.style.display = viewStyle;
            textEditor.style.display = editStyle;
            saveButton.style.display = editStyle;
            discardButton.style.display = editStyle;
        }

        editButton.onclick = function(){
            setMode("edit");
            textEditor.value = data;
        }

        saveButton.onclick = function(){
            data = textEditor.value;
            GM_setValue(user_id, data);
            textContainer.innerHTML = data.replace("\n", "<br/>");
            setMode("view");
        }

        discardButton.onclick = function(){
            setMode("view");
        }

        setMode("view");
        return container;
    }
    catch(e){
        console.log(e);
    }
}

function modify_popups(){
    try{
        var boxes = document.getElementsByClassName("popup user-popup");
        if (boxes.length > 0){
            var box = boxes[0];
            if(box.getElementsByClassName("usernotes").length > 0){
                //already added box to this popup
                return;
            }

            var links = box.getElementsByTagName("A");
            if (links.length > 0){
                var user_id = links[0].href.split("/")[4];
                box.insertBefore(makeArea(user_id), box.getElementsByTagName("BR")[0].nextSibling);
            }
        }
    }
    catch(e){
        console.log(e);
    }
}

try{
    setInterval(modify_popups, 500);
}
catch(e){
    console.log(e);
}

https://...