分析;

1.在页面上使用img标签展示图片

2 .定义一个方法,修改图片对象的src属性

3.定义一个定时器,每隔3秒调用方法一次。

 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script>
        var number = 1;
        function fun() {
            number++;
            if (number>3){
                number=1;
            }
            var img = document.getElementById("img");
            img.src = "img/banner_"+number+".jpg";
        }
        setInterval(fun,3000);
    </script>
</head>
<body>
    <img id="img" src="img/banner_1.jpg"width="400">
</body>
</html>

 

 

 

 

 

 

 

 

 

 

 

BOM_wWindow_属性

获取其他BOM对象:

history

localtion

Navigtor

Screen

获取DOM对象

  document

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

</head>
<body>
    <input id="openBtn" type="button" value="废铁"><script>
        // var  h1 = window.history;
        // var  h2 = history;
        // alert(h1)
        // alert(h2)

        var openBtn = window.document.getElementById("openBtn");
        alert(openBtn)
    </script>
</body>
</html>

 

 

 

 

posted on 2022-08-03 21:40  淤泥不染  阅读(45)  评论(0)    收藏  举报