<!DOCTYPE html>
<html>
<head>
<title>Window对象</title>
<meta charset="utf-8">
</head>
<body>
<a href="http://www.baidu.com">百度一下</a>
<button type="button" id="open">打开弹出层</button>
<div id="cover" style="display: none;position: fixed;width: 100%;height: 100%;top:0px;left:0px;background: gray;"> <!-- 通过遮罩层遮住背景 -->
<div style="background: lightblue;border:1px solid green;" id="toast"> <!-- 设置display属性为none以隐藏内容 -->
<p>这里是弹出层内容</p>
<button type="button" id="close">关闭弹出层</button>
</div>
</div>
<script type="text/javascript">
var toast = document.getElementById("toast");
var cover = document.getElementById("cover");
document.getElementById("open").onclick = function(e){ <!-- 定义点击事件显示隐藏内容 -->
cover.style.display = "block";
toast.style.position = "fixed";
var winWidth = window.innerWidth;
var winHeight = window.innerHeight;
var targetWidth = toast.offsetWidth;
var targetHeight = toast.offsetHeight;
toast.style.top = (winHeight - targetHeight) / 2 + "px";
toast.style.left = (winWidth - targetWidth) / 2 + "px";
}
document.getElementById("close").onclick = function(e){ <!-- 将显示的内容再次隐藏 -->
cover.style.display = "none";
}
</script>
</body>
</html>
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