JS实现简易图片轮播效果

2019PHP高薪工程师学习路线图....>>>

    <!DOCTYPE html>  
    <html lang="en">  
    <head>  
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />  
        <title>JS幻灯代码</title>  
        <script type="text/javascript">  
            window.onload = function () {  
                flag = 0;  
                obj1 = document.getElementById("slider");  
                obj2 = document.getElementsByTagName("li");  
                obj2[0].style.backgroundColor = "#666666";//默认被选中颜色  
                time = setInterval("turn();", 5000);  
      
                obj1.onmouseover = function () {  
                    clearInterval(time);  
                      
                }  
                obj1.onmouseout = function () {  
                    time = setInterval("turn();", 6000);  
                }  
      
                for (var num = 0; num < obj2.length; num++) {  
                    obj2[num].onmouseover = function () {  
                        turn(this.innerHTML);  
                        clearInterval(time);  
                    }  
                    obj2[num].onmouseout = function () {  
                        time = setInterval("turn();", 6000);  
                    }  
                }  
                //延迟加载图片,演示的时候,使用本地图片,上线后请改为二级域名提供的图片地址  
                document.getElementById("second").src = "images/2.png";//使用图片宽660,高550  
                document.getElementById("third").src = "images/3.png";  
                document.getElementById("four").src = "images/4.png";  
      
            }  
      
            function turn(value) {  
                if (value != null) {  
                    flag = value - 2;  
                }  
                if (flag < obj2.length - 1)  
                    flag++;  
                else  
                    flag = 0;  
                obj1.style.top = flag * (-550) + "px";  
                for (var j = 0; j < obj2.length; j++) {  
                    obj2[j].style.backgroundColor = "#ffffff";  
                }  
                obj2[flag].style.backgroundColor = "#666666";  
            }  
      
        </script>  
        <style type="text/css">  
            #wrap  
            {  
                height: 550px;  
                width: 660px;  
                overflow: hidden;  
                position: relative;  
                overflow: hidden;  
            }  
            #wrap ul  
            {  
                list-style: none;  
                position: absolute;  
                top: 500px;  
                left: 450px;  
            }  
            #wrap li  
            {  
                margin-left:2px;  
                opacity: .3;  
                filter: alpha(opacity=30);  
                text-align: center;  
                line-height: 30px;  
                font-size: 20px;  
                height: 30px;  
                width: 30px;  
                background-color: #fff;  
                float: left;  
                border-radius:3px;  
                cursor:pointer;  
            }  
      
            #slider  
            {  
                position: absolute;  
                top: 0px;  
                left: 0px;  
            }  
            #slider img  
            {  
                float: left;  
                border: none;  
            }  
        </style>  
    </head>  
    <body>  
        <div id="wrap">  
            <div id="slider">  
                <a target="_blank" href="#"><img src="images/1.png" /></a>  
                <a target="_blank" href="#"><img id="second" /></a>  
                <a target="_blank" href="#"><img id="third" /></a>  
                <a target="_blank" href="#"><img id="four" /></a>  
            </div>  
            <ul>  
                <li>1</li>  
                <li>2</li>  
                <li>3</li>  
                <li>4</li>  
            </ul>  
        </div>  
    </body>  
    </html>