Código simple para consultar mayoría de edad

checkBody = function(){
	if(document.body){
		document.body.innerHTML += '<div id="edadFixed" style="z-index:99999;position:fixed;background:black;top:0;left:0;width:100%;height:100%;color:white;font-size:30px"><div style="font-weigth:bold;text-align:center;position:absolute;top:40%;width:100%">¿Eres mayor de edad?<div style="margin-top:15px;width:100%;font-size:25px"><div style="width:200px;margin:0 auto"><div style="float:left;width:100px" onclick="document.getElementById(\'edadFixed\').style.display = \'none\'"><span style="cursor:pointer">Si</span></div><div style="float:right;width:100px;cursor:pointer" onclick="location.href=\'https://www.google.com\'"><span style="cursor:pointer">No</span></div></div></div></div></div>';
		clearInterval(waitBody);
	}
}
waitBody = setInterval(checkBody, 1);