<!DOCTYPE html>
<html lang="en">
<head>
</head>
<body>
<div style="width:900px; height:700px; overflow:hidden; border: 1px solid gray; position:relative;"></div>
<script>
var i = 1000;
while(i--) document.querySelector('div').insertAdjacentHTML('beforeend', '<div style="width:'+Math.random()*300+'px; height:'+Math.random()*300+'px; background-color:#'+Math.random().toString(16).slice(2,8)+'; top:'+(Math.random()*700-50)+'px; left:'+(Math.random()*900-50)+'px; position:absolute">'+Math.floor(Math.random()*9)+'</div>');
</script>
</script>
</body>
</html>
