JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="sidebar">
    
</ul>

JavaScript

var ifSrc = {"welcome":"welcome.html",
          "proceduresAndComputers":"../proceduresAndComputers/index.html",
          "someId":"../someSourceFileForAnIFrame"}


function createMenu(){
    var listy = document.getElementById("sidebar");
    for(var key in ifSrc){
        var elem = document.createElement('li');
        elem.innerHTML = key;
        elem.className = "unselected";
        elem.addEventListener("click", (function(k) {
            return function() { 
                openDiv(this, k);
            }
        })(key), false);
        listy.appendChild(elem);
    }
    listy.firstElementChild.className="selected";
}

function openDiv(e, key) {
     alert(key);   
}

createMenu();