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<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>
<p>y = 5, 计算 x = y--, y 和 x 为:</p>
<button onclick="myFunction()">点我</button>
<p><strong>注意:</strong> x 和 y的值将会改变。</p>
<p id="demo1"></p>
<p id="demo2"></p>
<script>
function myFunction() {
var y = 5;
var x = y--;
document.getElementById("demo1").innerHTML = "y 的值为:" + y;
document.getElementById("demo2").innerHTML = "x 的值为:" + x;
}
</script>
</body>
</html>