<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style type="text/css">
#big {
width: 200px;
height: 200px;
border: black 1px solid;
background-color: pink;
}
#red {
width: 20px;
height: 20px;
border: black 1px solid;
background-color: red;
margin: 10px;
float: left;
}
#green {
width: 20px;
height: 20px;
border: black 1px solid;
background-color: green;
margin: 10px;
float: left;
}
#blue {
width: 20px;
height: 20px;
border: black 1px solid;
background-color: blue;
margin: 10px;
float: left;
}
</style>
</head>
<body>
<div id="big">
<div id="red" onclick="change('red')"></div>
<div id="green" onclick="change('green')"></div>
<div id="blue" onclick="change('blue')"></div>
</div>
<script type="text/javascript">
function change(color) {
var big = document.getElementById("big");
big.style.backgroundColor = color
}
</script>
</body>
</html>
