text: //Black=0
  //White=1
  //Red=2
  //Green=3
  //Blue=4
  let number=-1,
  start=false,
  el = document.documentElement,
  rfs = // for newer Webkit and Firefox
  	el.requestFullScreen
  	|| el.webkitRequestFullScreen
  	|| el.mozRequestFullScreen
  	|| el.msRequestFullScreen;
  
  
  
  function startTest() {
  	document.getElementById("page").style.visibility= "hidden";
  
  	//This code whas copied from: https://hdeleon.net/cual-es-el-codigo-javascript-para-simular-la-tecla-f11-del-navegador-pantalla-completa-en-navegador/
  	//Props to them for the full screen compatibility
  	if(typeof rfs!="undefined" && rfs){
  		rfs.call(el);
  	} else if(typeof window.ActiveXObject!="undefined"){
  		// for Internet Explorer
  		var wscript = new ActiveXObject("WScript.Shell");
  		if (wscript!=null) {
  			wscript.SendKeys("{F11}");
  		}
  	}
  	start=true;
  	nextColour();
  }
  
  document.addEventListener('keydown', (e) => {
  	if (e.key==" "){
  		change();
  	}
  });
  
  document.addEventListener('click', () => {
  	change();
  });
  
  function change() {
  	if(start){
  		if(number<=3){
  			number++;
  		}else{
  			number=0;
  		}
  		nextColour();
  	}
  }
  
  function nextColour() {
  	console.log(number);
  	if(number==0){
  		document.body.style.backgroundColor = "#000000";
  	}else if(number==1){
  		document.body.style.backgroundColor = "#ffffff";
  	}else if(number==2){
  		document.body.style.backgroundColor = "rgb(255,0,0)";
  	}else if(number==3){
  		document.body.style.backgroundColor = "rgb(0,255,0)";
  	}else if(number==4){
  		document.body.style.backgroundColor = "rgb(0,0,255)";
  	}
  }