JSFiddle - React, Tailwind, and code Playground

HTML

<div id="log"></div>

CSS

#log {
    height: 256px;
    width: 512px;
    overflow: auto;
    border: 1px solid #ccc;
    margin: 15px auto;
    padding: 5px;
    contenteditable: true;
}

JavaScript

(function() {
    var Log = function(id) {
        this.log = document.getElementById(id);
    };
    
    Log.prototype.write = function(str) {
        this.log.innerHTML += str;
    };
    
    Log.prototype.writeLn = function(str) {
        this.write(str + '<br />');
    };
    
    var log = new Log('log');
    
    for(var i = 64; i-- > 0;) {
        log.writeLn('Hello JavaScript!');
    }
})();