jQuery_二级三级导航下拉效果

使用 jQuery 实现一个二级三级导航下拉效果。

效果图：

在线预览：jQuery_nav

GitHub地址

兼容性：

兼容性

HTML

<div class="nav">
    <div class="wrap">
        <ul class="first_ul">
            <li class="first_li">
                <a href="" class="first_a">首页</a>
            </li>
            <li class="first_li">
                <a href="" class="first_a">栏目一</a>
                <ul class="second_ul">
                    <li class="second_li">
                        <a href="" class="second_a">二级栏目1</a>
                    </li>
                    <li class="second_li">
                        <a href="" class="second_a">二级栏目2</a>
                    </li>
                    <li class="second_li">
                        <a href="" class="second_a">二级栏目3</a>
                    </li>
                </ul>
            </li>
            <li class="first_li">
                <a href="" class="first_a">栏目二</a>
            </li>
            <li class="first_li">
                <a href="" class="first_a">栏目三</a>
                <ul class="second_ul">
                    <li class="second_li">
                        <a href="" class="second_a">二级栏目1</a>
                    </li>
                    <li class="second_li">
                        <a href="" class="second_a">二级栏目2</a>
                        <ul class="third_ul">
                            <li class="third_li">
                                <a href="" class="third_a">三级栏目1</a>
                            </li>
                            <li class="third_li">
                                <a href="" class="third_a">三级栏目2</a>
                            </li>
                            <li class="third_li">
                                <a href="" class="third_a">三级栏目3</a>
                            </li>
                        </ul>
                    </li>
                    <li class="second_li">
                        <a href="" class="second_a">二级栏目3</a>
                        <ul class="third_ul">
                            <li class="third_li">
                                <a href="" class="third_a">三级栏目1</a>
                            </li>
                            <li class="third_li">
                                <a href="" class="third_a">三级栏目2</a>
                            </li>
                            <li class="third_li">
                                <a href="" class="third_a">三级栏目3</a>
                            </li>
                        </ul>
                    </li>
                </ul>
            </li>
            <div class="clear"></div>
        </ul>
    </div>
</div>

CSS

* { margin: 0; padding: 0; }
ul, li { list-style: none; }
a { -webkit-transition: all .3s; transition: all .3s; text-decoration: none; outline: none; }
.clear { clear: both; overflow: hidden; width: 100%; height: 0; }
.wrap { width: 1200px; margin: 0 auto; }
.nav { background-color: #105cb4; }
.first_li { position: relative; float: left; width: 160px; }
.first_a { line-height: 40px; display: block; height: 40px; text-align: center; color: #fff; border-left: 1px solid #fff; }
.first_a:hover { background-color: #074186; }
.second_ul { position: absolute; z-index: 1; top: 40px; left: 0; display: none; width: 100%; }
.second_a { line-height: 40px; display: block; height: 40px; text-align: center; color: #fff; border-top: 1px solid #fff; background-color: #105cb4; }
.second_a:hover { background-color: #074186; }
.third_ul { display: none; }
.have_third .second_a { position: relative; }
.have_third .sa_ico { position: absolute; top: 0; right: 0; width: 40px; height: 100%; background-image: url(ico01.png); background-repeat: no-repeat; background-position: center; }
.third_a { line-height: 30px; display: block; height: 30px; text-align: center; color: #333; background-color: #ececec; }
.third_a:hover { background-color: #cecece; }

JS

$(function() {
    $(".third_ul").parent().addClass('have_third');
    $(".have_third .second_a").append('<span class="sa_ico"></span>');

    $(".first_a").mouseenter(function(event) {
        $(this).next(".second_ul").stop(false, true).slideDown(400);
    });
    $(".first_li").mouseleave(function(event) {
        $(this).children(".second_ul").stop(false, true).slideUp(400);
    });
    $(".second_a").click(function(event) {
        event.preventDefault();
        $(this).next('.third_ul').stop(false, true).slideToggle(400);
    });
});

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