web导航栏设置设置导航栏

设置导航栏，文字为a,b
点击a显示1，2
点击b显示3，4


<!DOCTYPE html>
<html>

    <head>
        <meta charset="UTF-8">

        <script src="https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
        <style>
            * {
                margin: 0;
                padding: 0;
            }
            
            li {
                list-style: none;
            }
            
            #nav {
                margin: 50px;
                position: relative;
            }
            
            #nav li.current a {
                color: #f60;
            }
            
            #nav li {
                float: left;
                padding: 0 20px;
                height: 25px;
                position: relative;
            }
            
            #nav li a {
                font: 14px/25px '宋体';
                font-weight: bold;
                color: #000;
                text-decoration: none;
            }
            
            #nav li ul {
                display: none;
                position: absolute;
                left: 0;
                top: 25px;
                border: 1px solid #ccc;
                text-align: center;
                background: #f00;
            }
        </style>
    </head>

    <body>
        <script type="text/javascript">
            $(function() {
                $('#nav > li').click(function() { //hover是鼠标悬浮，click是鼠标点击。
                    $(this).addClass('current').siblings('li').removeClass('current');
                    $('#nav > li > ul').hide();
                    $(this).find('ul').show();
                })
            })
        </script>
        <ul id="nav">
            <li>
                <a href="#">a</a>
                <ul>
                    <li>
                        <a href="#">1</a>
                    </li>
                    <li>
                        <a href="#">2</a>
                    </li>
                </ul>
            </li>
            <li>
                <a href="#">b</a>
                <ul>
                    <li>
                        <a href="#">3</a>
                    </li>
                    <li>
                        <a href="#">4</a>
                    </li>
                </ul>
            </li>
        </ul>
    </body>

</html>