<head>
<meta charset="utf-8">
</head>
<body>
<style>
#id{
width: 100px;
height: 100px;
background-color: red;
</style>
<div id="id"></div>
<script>
var now = new Date();
if (now.getHours()>=17 && now.getHours()<23 || (now.getDay()==0 || now.getDay()==5 || now.getDay()==6) && now.getHours()>=17 ) document.getElementById("id").style.backgroundColor ="green";
</script>
</body>