Javascript for emulating a rudimentary console in jsfiddle

jsfiddle_console.js

document.addEventListener('DOMContentLoaded', function(){

document.querySelector('head').innerHTML +='<link type="text/css" href="https://gist.githubusercontent.com/kennasoft/d4f8594f7a06751b73dfb6a6cf4390ed/raw/524aa1bf26da6c2f336872ffe98fdfd89106412f/console.css" rel="stylesheet"/>'

var consoleHTML = `
	<footer id="console-toggle">
  	<div class="console"></div>
  </footer>
`;

document.body.innerHTML += consoleHTML;

if (!Element.prototype.matches)
    Element.prototype.matches =
        Element.prototype.msMatchesSelector ||
        Element.prototype.webkitMatchesSelector;
document.querySelector('#console-toggle').addEventListener('click', function(evt){
	let target = document.querySelector('#console-toggle');
  if(target.matches('.open')){
  	target.classList.remove('open')
  }else{
  	target.classList.add('open');
  }
})

window.console = {
  log: (output) => {
    if (typeof output !== 'string' && typeof output !== 'number') {
      output = JSON.stringify(output);
    }
    document.querySelector('.console').innerHTML += `<p class="console-log">${output}</p>`
  },
  error: (output) => {
    if (typeof output !== 'string' && typeof output !== 'number') {
      output = JSON.stringify(output);
    }
    document.querySelector('.console').innerHTML += `<p class="console-error">${output}</p>`
  }
}

});