<!DOCTYPE html>
<html>
<body>
<p id="demo"></p>
<script>
var x = 5; // 初始化 x
elem = document.getElementById("demo"); // 查找元素
elem.innerHTML = "x is " + x + " and y is " + y; // 显示 x 和 y
var y = 7; // Initialize y
</script>
</body>
</html>