在悬停时显示subMenu

Question

我有一个菜单，除了子菜单外，每个菜都有效。当子菜单的<li>为hover时，它假设显示子菜单，并且确实如此。但问题在于子菜单的位置，它没有在<li>下显示它left: 0%。

http://jsfiddle.net/2fDQz/1/ - 尝试将鼠标放在“admin”和“home”上。

这里是css（尽管你可以在jsfiddle中看到它）：

CSS

body {
}
/* Base Styles */
 #personalbar ul, #personalbar li, #personalbar a {
    list-style: none;
    margin: 0;
    padding: 0;
    border: 0;
    line-height: 1;
    font-family:'Lato', sans-serif;
}
#personalbar {
    border: 1px solid #123e3f;
    width: auto;
}
#personalbar ul {
    zoom: 1;
    background: #33b3b7;
    background: -moz-linear-gradient(top, #33b3b7 0%, #288c8f 100%);
    background: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #33b3b7), color-stop(100%, #288c8f));
    background: -webkit-linear-gradient(top, #33b3b7 0%, #288c8f 100%);
    background: -o-linear-gradient(top, #33b3b7 0%, #288c8f 100%);
    background: -ms-linear-gradient(top, #33b3b7 0%, #288c8f 100%);
    background: linear-gradient(top, #33b3b7 0%, #288c8f 100%);
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='@top-color', endColorstr='@bottom-color', GradientType=0);
    padding: 5px 10px;
}
#personalbar ul:before {
    content:'';
    display: block;
}
#personalbar ul:after {
    content:'';
    display: table;
    clear: both;
}
#personalbar li {
    float: left;
    margin: 0 5px 0 0;
    border: 1px solid transparent;
}
#personalbar li a {
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    -ms-border-radius: 5px;
    -o-border-radius: 5px;
    border-radius: 5px;
    padding: 8px 15px 9px 15px;
    display: block;
    text-decoration: none;
    color: #ffffff;
    border: 1px solid transparent;
    font-size: 16px;
}
#personalbar li.active {
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    -ms-border-radius: 5px;
    -o-border-radius: 5px;
    border-radius: 5px;
    border: 1px solid #33b3b7;
}
#personalbar li.active a {
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    -ms-border-radius: 5px;
    -o-border-radius: 5px;
    border-radius: 5px;
    display: block;
    background: #1d6567;
    border: 1px solid #123e3f;
    -moz-box-shadow: inset 0 5px 10px #123e3f;
    -webkit-box-shadow: inset 0 5px 10px #123e3f;
    box-shadow: inset 0 5px 10px #123e3f;
}
#personalbar li:hover {
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    -ms-border-radius: 5px;
    -o-border-radius: 5px;
    border-radius: 5px;
    border: 1px solid #33b3b7;
}
#personalbar li:hover a {
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    -ms-border-radius: 5px;
    -o-border-radius: 5px;
    border-radius: 5px;
    display: block;
    background: #1d6567;
    border: 1px solid #123e3f;
    -moz-box-shadow: inset 0 5px 10px #123e3f;
    -webkit-box-shadow: inset 0 5px 10px #123e3f;
    box-shadow: inset 0 5px 10px #123e3f;
}
#personalbar ul ul li:hover a, #personalbar li:hover li a {
    background: none;
    border: none;
    color: #666;
    -webkit-box-shadow: none;
    -moz-box-shadow: none;
}
#personalbar ul ul a:hover {
    background: #7d7d7d;
    color: #fff !important;
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    border-radius: 5px;
    text-shadow: 0 1px 1px rgba(0, 0, 0, 0.1);
}
#personalbar li:hover > ul {
    display: block;
}
#personalbar ul ul {
    position:absolute;
    z-index: 1000;
    display: none;
    margin: 0;
    padding: 0;
    width: 185px;
    top: 40px;
    left: 0;
    background: #ffffff;
    border: solid 1px #b4b4b4;
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    border-radius: 5px;
    -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
    -moz-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}
#personalbar ul ul li {
    position: relative;
    float: none;
    margin: 0;
    padding: 3px;
}

HTML：

<div id='personalbar' style="position:absolute; top:0%;left:0%; width:100%;">
    <ul>
        <li><a href='# '><span>Home</span></a>

            <ul>
                <li id="Li2" runat="server"><a id="A5" href="#" runat="server"><span>bla</span></a>
                </li>
                <li id="Li3" runat="server"><a id="A6" href="#" runat="server"><span>bli</span></a>
                </li>
            </ul>
        </li>
        <li id="L1" runat="server"><a id="A1" href="../ClientSide/newsFeed/allEr.aspx" runat="server"><span>My Wall</span></a>
        </li>
        <li id="L2" runat="server"><a id="A2" href="../ClientSide/employee/eeSettings.aspx" runat="server"><span>Setting</span></a>
        </li>
        <li id="Li1" runat="server"><a id="A4" href="../ClientSide/employee/eeSettings.aspx" runat="server"><span>Admin</span></a>

            <ul>
                <li runat="server"><a href="#" runat="server"><span>bla</span></a>
                </li>
                <li runat="server"><a href="#" runat="server"><span>bli</span></a>
                </li>
            </ul>
        </li>
        <li id="L3" runat="server" style="position:absolute; right:1%;"><a id="A3" href="../ClientSide/Registration/registration.aspx" runat="server"><span>Sign Up</span></a>
        </li>
    </ul>
</div>

我尝试将#personalbar ul ul的{​​{1}}更改为position，以下是做了什么：http://jsfiddle.net/2fDQz/2/

Answer 1

您需要将absolute定位元素包含在position: relative;容器中...

Demo

#personalbar li {
   float: left;
   margin: 0 5px 0 0;
   position: relative;
   border: 1px solid transparent;
}

---

请注意，正如@Amarnath指出的那样，在上面的演示中，菜单会在您悬停子元素时崩溃，这是因为您正在使用top: 40px;所以摆脱它 - {{3 }}

#personalbar ul ul {
    position:absolute;
    z-index: 1000;
    display: none;
    margin: 0;
    padding: 0;
    width: 185px;
    top: 40px; /* Take this out from here */
    left: 0;
    background: #ffffff;
    border: solid 1px #b4b4b4;
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    border-radius: 5px;
    -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
    -moz-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

---

另外，想建议你，当你处理这样的标记时，最好使用>选择器，这样你通过CSS选择的元素就是精确的..如果你不知道什么做那个选择器，它选择元素的直接子元素。例如使用

之类的东西

ul li ul {
   /* Selects all ul element nested under li */
}

而使用类似

的东西

ul > li > ul {
   /* Selects direct ul element nested under li - First Level */
}

Answer 2

您需要将所有li的位置设置为relative才能生效。制作position: relative内容会重置任何子元素的定位值。在相对定位的父级内部使用绝对定位时，子级（例如，设置为left: 0; top: 0;时）将自己定位到父级的左上边缘而不是文档。值得注意的一点是，z-index属性也相对于父级重置。

试试这个：

body {}
/* Base Styles */

#personalbar ul,
#personalbar li,
#personalbar a {
  list-style: none;
  margin: 0;
  padding: 0;
  border: 0;
  line-height: 1;
  font-family: 'Lato', sans-serif;
}
#personalbar {
  border: 1px solid #123e3f;
  width: auto;
}
#personalbar ul {
  zoom: 1;
  background: #33b3b7;
  background: -moz-linear-gradient(top, #33b3b7 0%, #288c8f 100%);
  background: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #33b3b7), color-stop(100%, #288c8f));
  background: -webkit-linear-gradient(top, #33b3b7 0%, #288c8f 100%);
  background: -o-linear-gradient(top, #33b3b7 0%, #288c8f 100%);
  background: -ms-linear-gradient(top, #33b3b7 0%, #288c8f 100%);
  background: linear-gradient(top, #33b3b7 0%, #288c8f 100%);
  filter: progid: DXImageTransform.Microsoft.gradient(startColorstr='@top-color', endColorstr='@bottom-color', GradientType=0);
  padding: 5px 10px;
}
#personalbar ul:before {
  content: '';
  display: block;
}
#personalbar ul:after {
  content: '';
  display: table;
  clear: both;
}
#personalbar li {
  float: left;
  margin: 0 5px 0 0;
  border: 1px solid transparent;
  position: relative;     /* This is the important bit */
}
#personalbar li a {
  -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  -ms-border-radius: 5px;
  -o-border-radius: 5px;
  border-radius: 5px;
  padding: 8px 15px 9px 15px;
  display: block;
  text-decoration: none;
  color: #ffffff;
  border: 1px solid transparent;
  font-size: 16px;
}
#personalbar li.active {
  -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  -ms-border-radius: 5px;
  -o-border-radius: 5px;
  border-radius: 5px;
  border: 1px solid #33b3b7;
}
#personalbar li.active a {
  -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  -ms-border-radius: 5px;
  -o-border-radius: 5px;
  border-radius: 5px;
  display: block;
  background: #1d6567;
  border: 1px solid #123e3f;
  -moz-box-shadow: inset 0 5px 10px #123e3f;
  -webkit-box-shadow: inset 0 5px 10px #123e3f;
  box-shadow: inset 0 5px 10px #123e3f;
}
#personalbar li:hover {
  -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  -ms-border-radius: 5px;
  -o-border-radius: 5px;
  border-radius: 5px;
  border: 1px solid #33b3b7;
}
#personalbar li:hover a {
  -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  -ms-border-radius: 5px;
  -o-border-radius: 5px;
  border-radius: 5px;
  display: block;
  background: #1d6567;
  border: 1px solid #123e3f;
  -moz-box-shadow: inset 0 5px 10px #123e3f;
  -webkit-box-shadow: inset 0 5px 10px #123e3f;
  box-shadow: inset 0 5px 10px #123e3f;
}
#personalbar ul ul li:hover a,
#personalbar li:hover li a {
  background: none;
  border: none;
  color: #666;
  -webkit-box-shadow: none;
  -moz-box-shadow: none;
}
#personalbar ul ul a:hover {
  background: #7d7d7d;
  color: #fff !important;
  -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  border-radius: 5px;
  text-shadow: 0 1px 1px rgba(0, 0, 0, 0.1);
}
#personalbar li:hover > ul {
  display: block;
}
#personalbar ul ul {
  position: absolute;
  z-index: 1000;
  display: none;
  margin: 0;
  padding: 0;
  top: 40px;
  left: 0;
  background: #ffffff;
  border: solid 1px #b4b4b4;
  -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  border-radius: 5px;
  -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
  -moz-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}
#personalbar ul ul li {
  position: relative;
  float: none;
  margin: 0;
  padding: 3px;
}

<div id='personalbar' style="position:absolute; top:0%;left:0%; width:100%;">
  <ul>
    <li><a href='# '><span>Home</span></a>
      <ul>
        <li id="Li2" runat="server"><a id="A5" href="#" runat="server"><span>bla</span></a>
        </li>
        <li id="Li3" runat="server"><a id="A6" href="#" runat="server"><span>bli</span></a>
        </li>
      </ul>
    </li>
    <li id="L1" runat="server"><a id="A1" href="../ClientSide/newsFeed/allEr.aspx" runat="server"><span>My Wall</span></a>
    </li>
    <li id="L2" runat="server"><a id="A2" href="../ClientSide/employee/eeSettings.aspx" runat="server"><span>Setting</span></a>
    </li>
    <li id="Li1" runat="server"><a id="A4" href="../ClientSide/employee/eeSettings.aspx" runat="server"><span>Admin</span></a>
      <ul>
        <li runat="server"><a href="#" runat="server"><span>bla</span></a>
        </li>
        <li runat="server"><a href="#" runat="server"><span>bli</span></a>
        </li>
      </ul>
    </li>
    <li id="L3" runat="server" style="position:absolute; right:1%;"><a id="A3" href="../ClientSide/Registration/registration.aspx" runat="server"><span>Sign Up</span></a>
    </li>
  </ul>
</div>