function trigger(){
    b.innerHTML = f.value.replace(/ /g, "&nbsp;").replace(/\n/g, "<br>");
		b.scrollLeft = f.scrollLeft;
		b.scrollTop = f.scrollTop;
	}
	var f = document.getElementById("front");
	var b = document.getElementById("back");
	f.addEventListener('change', trigger);
	f.addEventListener('blur', trigger);
	f.addEventListener('mouseup', trigger);
	f.addEventListener('mousedown', trigger);
	f.addEventListener('keydown', trigger);
	f.addEventListener('keyup', trigger);
	f.addEventListener('scroll', trigger);