声明

阅读本文需要有一定的HTML、CSS和JavaScript基础


设计

实现弹出层效果的思路非常简单:将待显示的内容先隐藏,在触发某种条件后(如点击按钮),将原本隐藏的内容显示出来。


实现

 

<!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 style="display: none;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>
<script type="text/javascript">
    var toast = document.getElementById("toast");
    document.getElementById("open").onclick = function(e){           <!--    定义点击事件显示隐藏内容          -->
        toast.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         -->
        toast.style.display = "none";
    }
</script>
</body>
</html>

 

显示效果如下:

但是我们可以注意到,在弹出隐藏内容之后我们还是可以通过链接进入百度页面。为了防止这种情况的发生,我们可以提供遮罩层将原先的页面内容全部遮住。代码如下:

<!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>

这是再次测试下效果,如下图:


总结

上述内容只是简单实现了弹出层效果,但是通过添加更多的代码也可以在此基础上实现更复杂的功能。