how to put one div over another
<!DOCTYPE html>
<html lang="en">
<head>
<title>Web page</title>
</head>
<body>
<div id="overlay">
</div>
<div id="originalDiv">
</div>
</body>
<style>
#overlay {
width: 100px;
height: 100px;
background-color: red;
z-index: -1;
position:absolute;
top:50px;
left:50px;
}
#originalDiv {
width: 100px;
height: 100px;
background-color: blue;
z-index: 1;
position:absolute;
top:0px;
left:0px;
}
</style>
</html>