效果如上。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>变换色</title>
    <script src="./jQuery/jquery-3.3.1.min.js"></script>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        .box {
            position: absolute;
            top: 40px;
            right: 40px;
            background: #9b59b6;
            padding: 10px;
        }
        .box a {
            display: block;
            float: left;
            height: 40px;
            width: 40px;
            /* margin: 10px; */
        }
        .box a:hover {
            border: white 1px solid;
        }
        #blue {
            background-color: #3498db;
        }
        #green {
            background-color: #2ecc71;
        }
        #red {
            background-color: #e74c3c;
        }
        #white {
            background-color: #ecf0f1;
        }
        #orange {
            background-color: #e67e22;
        }
    </style>
    <script>
        $(function() {
            $('a').click(function() {
                $('body').css('background-color', $(this).css('background-color'))
            })
        })
    </script>
</head>
<body>
    <div class="box">
        <a href="#" id="red"></a>
        <a href="#" id="green"></a>
        <a href="#" id="orange"></a>
        <a href="#" id="blue"></a>
        <a href="#" id="white"></a>
    </div>
</body>
</html>