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| <!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1">
<title></title>
<style type="text/css">
:root {
--bg: white;
}
body {
background-color: var(--bg);
}
</style>
</head>
<body>
<button type="button" id="red">红</button>
<button type="button" id="blue">蓝</button>
<button type="button" id="green">绿</button>
<script type="text/javascript">
["red", "blue", "green"].forEach(value => {
const btn = document.getElementById(`${value}`);
btn.addEventListener("click", () => {
document.body.style.setProperty("--bg", value);
});
});
</script>
</body>
</html>
|
