【Web】JavaScript实现轮播图效果

迷南。 2023-02-28 01:23 174阅读 0赞

轮播图就是网页到达一定时间就切换图片。要用到定时器功能，直接改变img的src

**代码：**

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>轮播图</title>
    </head>
    <body>
        <img id="img" src="img/banner_1.jpg" width="100%">
        <script>
            //修改图片src属性
            var number = 1;
            function f() { 
                number++;
                if (number > 3) { 
                    number = 1;
                }
                var img = document.getElementById("img");
                img.src = "img/banner_" + number + ".jpg";
            }
            //每隔3秒切换一次
            setInterval(f,3000);
        </script>
    
    </body>
    </html>

**运行效果：** 每隔3秒切换一次  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDY2ODg5OA_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDY2ODg5OA_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDY2ODg5OA_size_16_color_FFFFFF_t_70 2]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDY2ODg5OA_size_16_color_FFFFFF_t_70]: /images/20230209/5280710189514daeb3e3a0364b4025ee.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDY2ODg5OA_size_16_color_FFFFFF_t_70 1]: /images/20230209/a6893a7ff38b483c919ebc55c567b1ae.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDY2ODg5OA_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/2020071820315044.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDY2ODg5OA==,size_16,color_FFFFFF,t_70