JQuery/JavaScript 下拉菜单不起作用

Question

好的，所以我有一个我正在尝试制作的网站，并且有一个应该可以使用的下拉菜单。我什至已经使用这里的答案之一来获取此菜单的代码，创建了所有适当的类和所有内容，但它仍然无法正常工作。我的意思是，它实际上只是静静地坐在那里。它应该从图像中掉落。

HTML

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>NEStalgia::Home</title>
        <link rel="stylesheet" href="assets.css">
        <script src="main.js"></script>
    </head>
    <body>
        <div id="wrapper">
            <div id="header">
                <img src="images/header.png" alt="NEStalgia" href="index.html" class="header_menu"/>
                <br />
                <ul class="hover">
                    <li class="hoverli">
                        <img src="images/menubricks.png" alt="menu bar" class="menu_class" />
                        <ul class="file_menu">
                            <li><a href="index.html">Home</a></li>
                            <li><a href="aboutus.html">About Us</a></li>
                            <li><a href="shop.html">Shop</a>
                                <ul class="sub">
                                    <li><a href="headware.html">Headwear</a></li>
                                    <li><a href="apparel.html">Apparel</a></li>
                                    <li><a href="accessories.html">Accessories</a></li>
                                    <li><a href="cosplays.html">Cosplays</a></li>
                                    <li><a href="plushies.html">Plushies</a></li>
                                </ul>
                            </li>
                            <li><a href="registration.html">Register</a></li>
                            <li><a href="contactus.html">Contact Us</a></li>
                        </ul>
                    </li>
                </ul>
            </div>
            <div id="content">
                <div id="tableinfo">
                    <table id="intro"> 
                        <tr>
                            <td>Welcome to NEStalgia.<br />
                            We are a gaming merchandise online store that takes great 
                            pride in our work. We have hundreds of great options between
                            several categories: headwear, apparel, accessories, and so
                            many more!</td>
                            <td>&nbsp;</td>
                            <td>&nbsp;</td>
                            <td>&nbsp;</td>
                            <td>
                                <a href="headwear.html"><img src="images/headwear.png" alt="headwear" /></a>
                                <a href="apparel.html"><img src="images/apparel.png" alt="apparel" /></a>
                                <a href="accessories.html"><img src="images/accessories.png" alt="accessories" /></a>
                            </td>
                        </tr>
                        <tr>
                            <td>Don't forget to check out<br />
                            our coupons page! It's filled with TONS of wonderful coupons
                            that you're sure to love, like 50% off your entire purchase! 
                            Check in every Friday to see the coupons page updated, and be wary: 
                            some coupons start on a specific day, so until that day, you aren't
                            able to use them!</td>
                            <td>&nbsp;</td>
                            <td>&nbsp;</td>
                            <td>&nbsp;</td>
                            <td>
                                <a href="cosplays.html"><img src="images/cosplays.png" alt="cosplays" /></a>
                                <a href="plushies.html"><img src="images/plushies.png" alt="plushies" /></td></a>
                        </tr>
                    </table>
                </div>
            </div>
            <div id="footer">
                <footer>
                    <table id="tablefoot">
                        <tr>
                            <td>&copy; Copyright NEStalgia 2015<br />
                            All rights reserved. </td>
                            <td>Disclaimer: The images used on this site<br />
                            have been taken from Google Images. Do not search<br />
                            for this site on Facebook as it is a mock storefront<br />
                            for a final project. Do not attempt to purchase anything<br />
                            from this site either. Thank you for your understanding<br />
                            and cooperation.</td>
                            <td>Interested in keeping up with us?<br />
                            Be sure to check out our Facebook page!</td>
                        </tr>
                    </table>
                </footer>
            </div>
        </div>
    </body>
</html>

CSS

html, body {
    padding: 0px;
    margin: 0px;
    margin-right: 0px;
    height: 100%
}
body {
    background: url('images/mariostar.png') top left repeat-y,
                url('images/mariostar.png') top right repeat-y;
    background-color: white;
    color: black;
    font-family: Arial, Helvetica, sans-serif;
    height: 2000px;
}
a { 
    text-decoration: none; 
}
footer {
    padding-top: 55px;
    padding-bottom: 25px;
}
img {
    z-index: 1;
}
li { 
    list-style: none;
}
.container {
    position: relative;
    width: 920px;
    margin: 30px auto;
}
.container #product {
    position: relative;
    z-index: 2;
    float: left;
    width: 670px;
}
.container #sidebar {
    position: relative;
    z-index: 1;
    float: right;
    width: 224px;
}
.file_menu {
    display:none;
    width:300px;
    border: 1px solid #1c1c1c;
    position: relative;
}

.file_menu li {
    background-color: #302f2f;
    position: relative;
}

.file_menu li a {
    color:#FFFFFF; 
    text-decoration:none; 
    padding:10px; 
    display:block;
}

.file_menu li a:hover {
    padding:10px;
    font-weight:bold;
    color: #F00880;
}
.menu_class {
    border:1px solid #1c1c1c;
}
.sub {
    position: absolute;
    width:300px;
    border: 1px solid #1c1c1c;
    display: none;
    left: 302px;
    top: 0px;
}
#content {
    padding-bottom: 200px;
}
#footer {
    border-left: 10px solid #5AB3FF;
    border-right: 9px solid #5AB3FF;
    background: #A0D3FF;
    color: black;
    text-align: center;
    width: 98.65%;
    height: 200px;
    position: absolute;
    bottom: 0;
    left: 0;
}
#header {
    text-align: center;
    padding: 10px;
}
#header img {
    margin-left: 3px;
}
#header ul li {
    list-style-type: none;
    margin: 0px;
}
#header ul li a {
    text-decoration: none;
}
#intro {
    text-align: left;
    margin-right: 5px;
    width: 1100px;
}
#intro img {
    margin: 5px;
}
#intro tr td:first-of-type {
    width: 250px;
}
#intro tr td:last-of-type {
    width: 800px;
    text-align: center;
}
#intro td:first-of-type:first-line {
    text-transform: uppercase;
    color: #5AB3FF;
    font-weight: bold;
}
#tablefoot {
    padding-left: 100px;
    width: 1300px;
}
#tablefoot tr td {
    font-size: 10px;
}
#tableinfo {
    margin-left: 125px;
    margin-top: 50px;
    margin-bottom: 50px;
}
#wrapper {
    min-height:100%;
    position:relative;
}

JavaScript & JQuery

$(document).ready(function () {
    $(".hoverli").hover(
  function () {
     $('ul.file_menu').slideDown('medium');
  }, 
  function () {
     $('ul.file_menu').slideUp('medium');
  }
);

     $(".file_menu li").hover(
  function () {
     $(this).children("ul").slideDown('medium');
  },
  function () {
    $(this).children("ul").slideUp('medium');
  }
);
});

Fiddle http://jsfiddle.net/yutikohercell/68u51juh/light/

实时预览 http://jsfiddle.net/yutikohercell/68u51juh/embedded/result/

Answer 1

尝试使用 preventdefault 和 stopimmediatepropagation：

$(function () {
  $(".hoverli").hover(
    function() {
      $('ul.file_menu').slideDown('medium');
    },
    function() {
      event.preventDefault();
      $('ul.file_menu').slideUp('medium');
    }
  );

  $(".file_menu li").hover(
    function() {
      event.preventDefault();
      event.stopImmediatePropagation();
      $(this).children("ul").slideDown('medium');
    },
    function() {
      event.preventDefault();
      event.stopImmediatePropagation();
      $(this).children("ul").slideUp('medium');
    }
  );
});

html,
body {
  padding: 0px;
  margin: 0px;
  margin-right: 0px;
  height: 100%
}

body {
  background: url('images/mariostar.png') top left repeat-y, url('images/mariostar.png') top right repeat-y;
  background-color: white;
  color: black;
  font-family: Arial, Helvetica, sans-serif;
  height: 2000px;
}

a {
  text-decoration: none;
}

footer {
  padding-top: 55px;
  padding-bottom: 25px;
}

img {
  z-index: 1;
}

li {
  list-style: none;
}

.container {
  position: relative;
  width: 920px;
  margin: 30px auto;
}

.container #product {
  position: relative;
  z-index: 2;
  float: left;
  width: 670px;
}

.container #sidebar {
  position: relative;
  z-index: 1;
  float: right;
  width: 224px;
}

.file_menu {
  display: none;
  width: 300px;
  border: 1px solid #1c1c1c;
  position: relative;
}

.file_menu li {
  background-color: #302f2f;
  position: relative;
}

.file_menu li a {
  color: #FFFFFF;
  text-decoration: none;
  padding: 10px;
  display: block;
}

.file_menu li a:hover {
  padding: 10px;
  font-weight: bold;
  color: #F00880;
}

.menu_class {
  border: 1px solid #1c1c1c;
}

.sub {
  position: absolute;
  width: 300px;
  border: 1px solid #1c1c1c;
  display: none;
  left: 302px;
  top: 0px;
}

#content {
  padding-bottom: 200px;
}

#footer {
  border-left: 10px solid #5AB3FF;
  border-right: 9px solid #5AB3FF;
  background: #A0D3FF;
  color: black;
  text-align: center;
  width: 98.65%;
  height: 200px;
  position: absolute;
  bottom: 0;
  left: 0;
}

#header {
  text-align: center;
  padding: 10px;
}

#header img {
  margin-left: 3px;
}

#header ul li {
  list-style-type: none;
  margin: 0px;
}

#header ul li a {
  text-decoration: none;
}

#intro {
  text-align: left;
  margin-right: 5px;
  width: 1100px;
}

#intro img {
  margin: 5px;
}

#intro tr td:first-of-type {
  width: 250px;
}

#intro tr td:last-of-type {
  width: 800px;
  text-align: center;
}

#intro td:first-of-type:first-line {
  text-transform: uppercase;
  color: #5AB3FF;
  font-weight: bold;
}

#tablefoot {
  padding-left: 100px;
  width: 1300px;
}

#tablefoot tr td {
  font-size: 10px;
}

#tableinfo {
  margin-left: 125px;
  margin-top: 50px;
  margin-bottom: 50px;
}

#wrapper {
  min-height: 100%;
  position: relative;
}

<script src="//code.jquery.com/jquery-1.11.3.js"></script>


<div id="wrapper">
    <div id="header">
        <ul class="hover">
            <li class="hoverli">
                <img src="http://i67.tinypic.com/2dafuyc.jpg" alt="menu bar" class="menu_class" />
                <ul class="file_menu">
                    <li><a href="index.html">Home</a></li>
                    <li><a href="aboutus.html">About Us</a></li>
                    <li><a href="shop.html">Shop</a>
                        <ul class="sub">
                            <li><a href="headware.html">Headwear</a></li>
                            <li><a href="apparel.html">Apparel</a></li>
                            <li><a href="accessories.html">Accessories</a></li>
                            <li><a href="cosplays.html">Cosplays</a></li>
                            <li><a href="plushies.html">Plushies</a></li>
                        </ul>
                    </li>
                    <li><a href="registration.html">Register</a></li>
                    <li><a href="contactus.html">Contact Us</a></li>
                </ul>
            </li>
        </ul>
    </div>
</div>

Answer 2

您需要添加jQuery，否则将无法运行。

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