html - 标签栏中的 CSS 下拉菜单消失

Question

我是编码新手，在使下拉菜单正常工作时遇到了一些问题。

当我的光标悬停在相应的选项卡上时，菜单会正确地下拉，但是一旦我将光标向下移动到实际的下拉子类别，它们就会消失。

这是标签的 CSS:

#cssmenu {
  position: relative;
  height: 44px;
  background: #1d309e;
  width: auto;
  z-index: 100;
}
#cssmenu ul {
  list-style: none;
  padding: 0;
  margin: 0;
  line-height: 1;
}
#cssmenu > ul {
  position: relative;
  display: block;
  background: #1d309e;
  height: 32px;
  width: 100%;
  z-index: 99;
  text-transform:lowercase;
}
#cssmenu > ul > li {
  display: block;
  position: relative;
  float: left;
  margin: 0;
  padding: 0;
  font-family: tahoma, "Trebuchet MS", verdana, helvetica, arial, sans-serif;
  text-transform:lowercase
  z-index: 100
}
#cssmenu > ul > #menu-button {
  display: none;
}
#cssmenu ul li a {
  display: block;
  font-family: tahoma, "Trebuchet MS", verdana, helvetica, arial, sans-serif;
  text-decoration: none;
  text-transform:lowercase
}
#cssmenu > ul > li > a {
  font-size: 15px;
  padding: 0px 80px;
  color: #ffffff;
  -webkit-transition: color 0.25s ease-out;
  -moz-transition: color 0.25s ease-out;
  -ms-transition: color 0.25s ease-out;
  -o-transition: color 0.25s ease-out;
  transition: color 0.25s ease-out;
  text-transform:lowercase
}
#cssmenu > ul > li.has-sub > a {
  padding-right: 32px;
}
#cssmenu > ul > li:hover > a {
  color: #fff203;
}
#cssmenu li.has-sub::after {
  display: block;
  content: '';
  position: absolute;
  width: 0;
  height: 0;
  z-index: 100
}
#cssmenu > ul > li.has-sub::after {
  right: 10px;
  top: 20px;
  border: 5px solid transparent;
  border-top-color: #ffffff;
}
#cssmenu > ul > li:hover::after {
  border-top-color: #fff203;
}
#indicatorContainer {
  position: absolute;
  height: 12px;
  width: 100%;
  bottom: 0px;
  overflow: hidden;
  z-index: 100;
}
#pIndicator {
  position: absolute;
  height: 0;
  width: 100%;
  border: 12px solid transparent;
  border-top-color: #2b2f3a;
  z-index: 100;
  -webkit-transition: left .25s ease;
  -moz-transition: left .25s ease;
  -ms-transition: left .25s ease;
  -o-transition: left .25s ease;
  transition: left .25s ease;
}
#cIndicator {
  position: absolute;
  height: 0;
  width: 100%;
  border: 12px solid transparent;
  border-top-color: #2b2f3a;
  top: -12px;
  right: 100%;
  z-index: 100;
}
#cssmenu ul ul {
  position: absolute;
  left: -9999px;
  top: 70px;
  opacity: 0;
  -webkit-transition: opacity .3s ease, top .25s ease;
  -moz-transition: opacity .3s ease, top .25s ease;
  -ms-transition: opacity .3s ease, top .25s ease;
  -o-transition: opacity .3s ease, top .25s ease;
  transition: opacity .3s ease, top .25s ease;
  z-index: 100;
}
#cssmenu ul ul ul {
  top: 37px;
  padding-left: 5px;
}
#cssmenu ul ul li {
  position: relative;
  z-index: 100
}
#cssmenu > ul > li:hover > ul {
  left: auto;
  top: 44px;
  opacity: 1;
}
#cssmenu ul ul li:hover > ul {
  left: 170px;
  top: 0;
  opacity: 1;
}
#cssmenu ul ul li a {
  width: 130px;
  border-bottom: 1px solid #eee;
  padding: 10px 20px;
  font-size: 12px;
  color: #1d309e;
  background: #fff;
  -webkit-transition: all .35s ease;
  -moz-transition: all .35s ease;
  -ms-transition: all .35s ease;
  -o-transition: all .35s ease;
  transition: all .35s ease;
}
#cssmenu ul ul li:hover > a {
  background: #f6f6f6;
  color: #ffee00;
}
#cssmenu ul ul li:last-child > a,
#cssmenu ul ul li.last > a {
  border-bottom: 0;
}
.submenuArrow {
 border: 6px solid transparent;
  width: 0;
  height: 0;
  border-bottom-color: #fff;
  position: absolute;
  top: -12px;
}
#cssmenu ul ul li.has-sub::after {
  border: 4px solid transparent;
  border-left-color: #1d309e;
  right: 10px;
  top: 12px;
  -moz-transition: all .2s ease;
  -ms-transition: all .2s ease;
  -o-transition: all .2s ease;
  transition: all .2s ease;
  -webkit-transition: -webkit-transform 0.2s ease, right 0.2s ease;
}
#cssmenu ul ul li.has-sub:hover::after {
  border-left-color: #fff;
  right: -5px;
  -webkit-transform: rotateY(180deg);
  -ms-transform: rotateY(180deg);
  -moz-transform: rotateY(180deg);
  -o-transform: rotateY(180deg);
  transform: rotateY(180deg);
}
@media all and (max-width: 800px), only screen and (-webkit-min-device-pixel-ratio: 2) and (max-width: 1024px), only screen and (min--moz-device-pixel-ratio: 2) and (max-width: 1024px), only screen and (-o-min-device-pixel-ratio: 2/1) and (max-width: 1024px), only screen and (min-device-pixel-ratio: 2) and (max-width: 1024px), only screen and (min-resolution: 192dpi) and (max-width: 1024px), only screen and (min-resolution: 2dppx) and (max-width: 1024px) {
  #cssmenu {
    width: auto;
  }
  #cssmenu ul {
    width: auto;
  }
  #cssmenu .submenuArrow,
  #cssmenu #indicatorContainer {
    display: none;
  }
  #cssmenu > ul {
    height: auto;
    display: block;
  }
  #cssmenu > ul > li {
    float: none;
  }
  #cssmenu li,
  #cssmenu > ul > li {
    display: none;
  }
  #cssmenu ul ul,
  #cssmenu ul ul ul,
  #cssmenu ul > li:hover > ul,
  #cssmenu ul ul > li:hover > ul {
    position: relative;
    left: auto;
    top: auto;
    opacity: 1;
    padding-left: 0;
    z-index: 100
  }
  #cssmenu ul .has-sub::after {
    display: none;
  }
  #cssmenu ul li a {
    padding: 12px 20px;
  }
  #cssmenu ul ul li a {
    border: 0;
    background: none;
    width: auto;
    padding: 8px 35px;
  }
  #cssmenu ul ul li:hover > a {
    background: none;
    color: #ffee00;
  }
  #cssmenu ul ul ul a {
    padding: 8px 50px;
  }
  #cssmenu ul ul ul ul a {
    padding: 8px 65px;
  }
  #cssmenu ul ul ul ul ul a {
    padding: 8px 80px;
  }
  #cssmenu ul ul ul ul ul ul a {
    padding: 8px 95px;
  }
  #cssmenu > ul > #menu-button {
    display: block;
    cursor: pointer;
  }
  #cssmenu #menu-button > a {
    padding: 14px 20px;
  }
  #cssmenu ul.open li,
  #cssmenu > ul.open > li {
    display: block;
  }
  #cssmenu > ul.open > li#menu-button > a {
    color: #fff;
    border-bottom: 1px solid rgba(150, 150, 150, 0.1);
  }
  #cssmenu #menu-button::after {
    display: block;
    content: '';
    position: absolute;
    height: 3px;
    width: 22px;
    border-top: 2px solid #ffffff;
    border-bottom: 2px solid #ffffff;
    right: 20px;
    top: 15px;
    z-index: 100
  }
  #cssmenu #menu-button::before {
    display: block;
    content: '';
    position: absolute;
    height: 3px;
    width: 22px;
    border-top: 2px solid #ffffff;
    right: 20px;
    top: 25px;
    z-index: 100
  }
  #cssmenu ul.open #menu-button::after,
 #cssmenu ul.open #menu-button::before {
    border-color: #fff;
  }
}

下面是我要放置的 HTML 页面:

<!DOCTYPE html>
<html>
<head>
<meta http-equiv='Content-Type' content='text/html; charset=utf-8' />
<meta http-equiv='X-UA-Compatible' content='IE=edge,chrome=1' />
<link rel='stylesheet' type='text/css' href='styles.css' />
<script src='http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js'>      
</script>
<script type='text/javascript' src='menu_jquery.js'></script>
</head>
<body>
<h1>Sugar Mule</h1>
<div id='cssmenu'>
<ul>
   <li class='active'><a href='index.html'><span>Home</span></a></li>
   <li class='has-sub'><a href='about.html'><span>About</span></a>
      <ul>
         <li><a href='why.html'><span>Why Sugar Mule?</span></a></li>
         <li><a href='staff.html'><span>Staff</span></a></li>
         <li class='last'><a href='contact.html'><span>Contact</span></a></li>
      </ul>
   </li>
   <li><a href='issues.html'><span>Issues</span></a></li>
   <li><a href='books.html'><span>Books</span></a></li>
   <li><a href='submit.html'><span>Submit</span></a></li>
   <li class='last'><a href='links.html'><span>Links</span></a></li>
</ul>
</div>
<center><img src="logo.png" alt="Logo" width="700" height="450"></center>
</body>
</html>

在此先感谢您的帮助!

Answer 1

因为下拉列表 #cssmenu > ul > li:hover > ul 的顶部偏移量为 44px。

那么你必须确保所有顶级链接 #cssmenu > ul > li > a 至少为 44px

这是修改后的 CSS

#cssmenu > ul > li > a {
    ...
    min-height:44px;
    ...
}

fiddle :http://jsfiddle.net/Varinder/bg763/