<!DOCTYPE html>
<html>
<head>
<title></title>
<script type="text/javascript">
var next = 0;
function addVisibleBox() {
var box = document.createElement('DIV');
box.id = 'box' + next++;
box.className = 'redbox';
box.style.width = '150px';
box.style.height = '150px';
box.style.backgroundColor = 'red';
box.style.border = '1px solid black';
box.style.margin = '5px';
box.style.visibility = 'visible'
window.setTimeout(function() {
document.body.appendChild(box);
}, 1000);
}
function addHiddenBox() {
var box = document.createElement('DIV');
box.id = 'box' + next++;
box.className = 'redbox';
box.style.width = '150px';
box.style.height = '150px';
box.style.backgroundColor = 'red';
box.style.border = '1px solid black';
box.style.margin = '5px';
box.style.visibility = 'hidden';
window.setTimeout(function() {
document.body.appendChild(box);
}, 1000);
}
</script>
</head>
<body>
<input id="addVisible" type="button" value="Add a visible box!" onclick="addVisibleBox()"/>
<input id="addHidden" type="button" value="Add a hidden box!" onclick="addHiddenBox();" />
</body>
</html>