如何在下拉菜单中将宽度设置为 100%

Question

你好，我想为我的下拉菜单提供 100% 的宽度，但是当我向左或向右浮动时，none 不起作用！我怎样才能给这个菜单 100% 的宽度？

我尝试显示但不起作用我试了 6 小时，如果有人能帮助我，我会很累，我真的很高兴 :) 抱歉我的英语不好

我的代码：

body,
ul,
li {
  margin: 0px;
  padding: 0px;
  background-color: #0CF;
}

li {
  font-family: verdana;
  font-size: 12px;
  color: #333;
  line-height: 40px;
  list-style-type: none;
  /* [disabled]list-style-image: url(../images/li.png); */
  background-color: #990;
  width: 100px;
  float: right;
  text-align: center;
  height: 40px;
  margin-left: 2px;
  display: block;
}

li ul {
  display: none;
  background-color: #CC0;
}

body ul li ul li {
  background-color: #F90;
  margin: 0px;
  padding: 0px;
  display: block;
}

li:hover {
  background-color: #CC0;
  cursor: pointer;
}

li:hover>ul {
  display: block;
}

<ul>
  <li>Item 1</li>
  <li>Item 2
    <ul>
      <li>Sub Item1</li>
      <li>Sub Item1</li>
      <li>Sub Item1</li>
    </ul>
  </li>
  <li>Item 3</li>
  <li>Item 4
    <ul>
      <li>Sub Item1</li>
      <li>Sub Item1</li>
      <li>Sub Item1</li>
    </ul>
  </li>
  <li>Item 5</li>
  <li>Item 6</li>
</ul>

喜欢这张图片： SHOW IMAGE:

Answer 1

改变CSS

li ul {
    display: none;
    background-color: #CC0;
    width:100%;
    position: absolute;
    left: 0;
}

body ul li ul li {
    background-color: #F90;
    margin: 0px;
    padding: 0px;
    display: block;
    float: left;
}

body,
ul,
li {
    margin: 0px;
    padding: 0px;
    background-color: #0CF;
}

li {
    font-family: verdana;
    font-size: 12px;
    color: #333;
    line-height: 40px;
    list-style-type: none;
    /* [disabled]list-style-image: url(../images/li.png); */
    background-color: #990;
    width: 100px;
    float: right;
    text-align: center;
    height: 40px;
    margin-left: 2px;
    display: block;
}

li ul {
    display: none;
    background-color: #CC0;
    width:100%;
    position: absolute;
    left: 0;
}

body ul li ul li {
    background-color: #F90;
    margin: 0px;
    padding: 0px;
    display: block;
    float: left;
}

li:hover {
    background-color: #CC0;
    cursor: pointer;
}

li:hover>ul {
    display: block;
}

<ul>
        <li>Item 1</li>
        <li>Item 2
            <ul>
                <li>Sub Item1</li>
                <li>Sub Item1</li>
                <li>Sub Item1</li>
            </ul>
        </li>
        <li>Item 3</li>
        <li>Item 4
            <ul>
                <li>Sub Item1</li>
                <li>Sub Item1</li>
                <li>Sub Item1</li>
            </ul>
        </li>
        <li>Item 5</li>
        <li>Item 6</li>
    </ul>

Answer 2

在下方添加css

body {background: #0CF;}
ul {width: 100%;list-style: none;padding: 0;margin: 0;}
body > ul {float: left;position: relative;border-bottom: 1px solid #000;}
body > ul > li {font-family: verdana;font-size: 12px;color: #333;line-height: 40px;float: right;padding: 0 20px;}
body > ul > li:hover ul {display: block;}
body > ul ul {display: none;position: absolute;top: 100%;left: 0;width: 100%;border-bottom: 1px solid #000;z-index: 1;}
body > ul ul > li {float: left;padding: 10px 20px;}

Answer 3

希望对您有所帮助。

body,
ul,
li {
  margin: 0px;
  padding: 0px;
  background-color: #0CF;
}

li {
  font-family: verdana;
  font-size: 12px;
  color: #333;
  line-height: 40px;
  list-style-type: none;
  /* [disabled]list-style-image: url(../images/li.png); */
  background-color: #990;
  width: 100px;
  float: right;
  text-align: center;
  height: 40px;
  margin-left: 2px;
  display: block;
}

li ul {
  display: none;
  background-color: #CC0;
}

body ul li ul li {
  background-color: #F90;
  margin: 0px;
  padding: 0px;
  display: block;
}

li:hover {
  background-color: #CC0;
  cursor: pointer;
}

li:hover>ul {
  display: block;
}

ul.sub {
  width: 100%;
  position: absolute;
  left: 0;
}

<ul>
  <li>Item 1</li>
  <li>Item 2
    <ul class="sub">
      <li>Sub Item1</li>
      <li>Sub Item1</li>
      <li>Sub Item1</li>
    </ul>
  </li>
  <li>Item 3</li>
  <li>Item 4
    <ul class="sub">
      <li>Sub Item1</li>
      <li>Sub Item1</li>
      <li>Sub Item1</li>
    </ul>
  </li>
  <li>Item 5</li>
  <li>Item 6</li>
</ul>

如何在下拉菜单中将宽度设置为 100%

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