例如这种,当然这只是一个例子,其他的也行,如果可以,请简要说明一下用到哪些技能点和原理。
回复内容:
几个下拉菜单display:none按钮 :hover 给下拉菜单display:block
也许可以 无脚本,纯HTML和 CSS 实现的多级下拉菜单,在非 IE 内核浏览器和 IE8+ 表现完美。

主体使用ul>li>ul>li>......嵌套定义多级。
<span class="cp"><!DOCTYPE HTML></span>
<span class="nt"><html></span>
<span class="nt"><head></span>
<span class="nt"><meta</span> <span class="na">http-equiv=</span><span class="s">"Content-Type"</span> <span class="na">content=</span><span class="s">"text/html; charset=utf-8"</span><span class="nt">></span>
<span class="nt"><title></span>纯 CSS 多级菜单<span class="nt"></title></span>
<span class="nt"><style></span>
<span class="nc">.menu</span><span class="p">{}</span>
<span class="nc">.menu</span> <span class="nt">ul</span><span class="o">,</span><span class="nc">.menu</span> <span class="nt">li</span><span class="p">{</span><span class="k">margin</span><span class="o">:</span><span class="m">0</span><span class="p">;</span> <span class="k">padding</span><span class="o">:</span><span class="m">0</span><span class="p">;</span><span class="k">list-style</span><span class="o">:</span><span class="k">none</span> <span class="k">outside</span><span class="p">;}</span>
<span class="nc">.menu</span><span class="o">></span><span class="nt">ul</span><span class="p">{</span><span class="k">overflow</span><span class="o">:</span><span class="k">auto</span><span class="p">;</span> <span class="k">display</span><span class="o">:</span><span class="k">inline</span><span class="o">-</span><span class="k">block</span><span class="p">;}</span>
<span class="nc">.menu</span> <span class="nt">a</span><span class="o">,</span><span class="nc">.menu</span> <span class="nt">span</span><span class="p">{</span> <span class="k">cursor</span><span class="o">:</span><span class="k">default</span><span class="p">;</span> <span class="k">height</span><span class="o">:</span><span class="m">30px</span><span class="p">;</span> <span class="k">line-height</span><span class="o">:</span><span class="m">30px</span><span class="p">;</span> <span class="k">padding</span><span class="o">:</span><span class="m">0</span> <span class="m">5px</span><span class="p">;</span> <span class="k">display</span><span class="o">:</span><span class="k">block</span><span class="p">;</span> <span class="k">text</span><span class="o">-</span><span class="k">overflow</span><span class="o">:</span><span class="n">ellipsis</span><span class="p">;</span> <span class="k">overflow</span><span class="o">:</span><span class="k">hidden</span><span class="p">;</span> <span class="k">text-decoration</span><span class="o">:</span><span class="k">none</span><span class="p">;</span> <span class="k">color</span><span class="o">:</span><span class="n">MenuText</span><span class="p">;}</span>
<span class="nc">.menu</span> <span class="nt">a</span><span class="nd">:hover</span><span class="o">,</span><span class="nc">.menu</span> <span class="nt">span</span><span class="nd">:hover</span><span class="o">,</span><span class="nc">.menu</span> <span class="nt">li</span><span class="nd">:hover</span><span class="o">></span><span class="nt">a</span><span class="o">,</span><span class="nc">.menu</span> <span class="nt">li</span><span class="nd">:hover</span><span class="o">></span><span class="nt">span</span><span class="p">{</span><span class="k">color</span><span class="o">:</span><span class="n">HighlightText</span><span class="p">;}</span>
<span class="nc">.menu</span> <span class="nt">li</span><span class="nd">:hover</span><span class="p">{</span><span class="k">background-color</span><span class="o">:</span><span class="n">Highlight</span><span class="p">;}</span>
<span class="nc">.menu</span> <span class="nt">li</span><span class="nd">:hover</span><span class="o">></span><span class="nt">ul</span><span class="p">{</span><span class="k">display</span><span class="o">:</span><span class="k">block</span><span class="p">;}</span>
<span class="nc">.menu</span><span class="o">></span><span class="nt">ul</span><span class="o">></span><span class="nt">li</span><span class="p">{</span><span class="k">float</span><span class="o">:</span><span class="k">left</span><span class="p">;}</span>
<span class="nc">.menu</span><span class="o">></span><span class="nt">ul</span><span class="o">></span><span class="nt">li</span> <span class="nt">ul</span><span class="p">{</span><span class="k">display</span><span class="o">:</span><span class="k">none</span><span class="p">;</span><span class="k">float</span><span class="o">:</span><span class="k">left</span><span class="p">;</span> <span class="k">background-color</span><span class="o">:</span><span class="m">#fff</span><span class="p">;</span> <span class="k">border</span><span class="o">:</span><span class="m">1px</span> <span class="k">solid</span> <span class="n">Highlight</span><span class="p">;</span> <span class="k">position</span><span class="o">:</span><span class="k">absolute</span><span class="p">;}</span>
<span class="nc">.menu</span><span class="o">></span><span class="nt">ul</span><span class="o">></span><span class="nt">li</span> <span class="nt">li</span><span class="p">{</span><span class="k">padding-left</span><span class="o">:</span><span class="m">25px</span><span class="p">;</span><span class="k">margin</span><span class="o">:</span><span class="m">2px</span><span class="p">;</span><span class="k">background</span><span class="o">:</span><span class="k">transparent</span> <span class="sx">url(data:image/gif;base64,R0lGODlhEAAQAIAAAJmZmf///yH5BAAAAAAALAAAAAAQABAAAAIjhI9pwe2+nmRRIQrmjBrmYB1Y93Ak+IXVd6LtiIZwa5JqWAAAOw==)</span> <span class="k">no-repeat</span> <span class="m">5px</span> <span class="k">center</span><span class="p">;</span> <span class="k">width</span><span class="o">:</span><span class="m">150px</span><span class="p">;}</span>
<span class="nc">.menu</span><span class="o">></span><span class="nt">ul</span><span class="o">></span><span class="nt">li</span><span class="o">></span><span class="nt">ul</span><span class="o">></span><span class="nt">li</span> <span class="nt">ul</span><span class="p">{</span><span class="k">margin-left</span><span class="o">:</span><span class="m">140px</span><span class="p">;</span> <span class="k">margin-top</span><span class="o">:-</span><span class="m">30px</span><span class="p">;}</span>
<span class="nc">.menu</span> <span class="nt">li</span><span class="nc">.expand</span><span class="o">></span><span class="nt">a</span><span class="o">,</span><span class="nc">.menu</span> <span class="nt">li</span><span class="nc">.expand</span><span class="o">></span><span class="nt">span</span><span class="p">{</span><span class="k">background</span><span class="o">:</span><span class="k">transparent</span> <span class="sx">url(data:image/png;base64,R0lGODlhAwAQAIABAAAAAP///yH5BAEAAAEALAAAAAADABAAAAIKjI8JBtv/wko0FQA7)</span> <span class="k">no-repeat</span> <span class="k">right</span> <span class="k">center</span><span class="p">;</span> <span class="k">padding-right</span><span class="o">:</span><span class="m">10px</span><span class="p">;</span> <span class="k">margin-right</span><span class="o">:</span><span class="m">5px</span><span class="p">;}</span>
<span class="nc">.menu</span><span class="o">></span><span class="nt">ul</span><span class="o">></span><span class="nt">li</span><span class="nc">.expand</span><span class="o">></span><span class="nt">a</span><span class="o">,</span><span class="nc">.menu</span><span class="o">></span><span class="nt">ul</span><span class="o">></span><span class="nt">li</span><span class="nc">.expand</span><span class="o">></span><span class="nt">span</span><span class="p">{</span> <span class="k">background-image</span><span class="o">:</span><span class="sx">url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAYAAAADCAYAAACwAX77AAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAaSURBVBhXY2BgYPiPAwOFMSXBgjAA0wnmAwASVQv19UVKmwAAAABJRU5ErkJggg==)</span><span class="p">;}</span>
<span class="nt"></style></span>
<span class="nt"></head></span>
<span class="nt"><body></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"mainnav"</span> <span class="na">class=</span><span class="s">"menu"</span><span class="nt">></span>
<span class="nt"><ul></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li</span> <span class="na">class=</span><span class="s">"expand"</span><span class="nt">><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></span>
<span class="nt"><ul></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li</span> <span class="na">class=</span><span class="s">"expand"</span><span class="nt">><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>很长很长很长很长很长很长很长很长很长很长<span class="nt"></a></span>
<span class="nt"><ul></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li</span> <span class="na">class=</span><span class="s">"expand"</span><span class="nt">><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>LinkLink<span class="nt"></a></span>
<span class="nt"><ul></span>
<span class="nt"><li</span> <span class="na">class=</span><span class="s">"expand"</span><span class="nt">><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></span>
<span class="nt"><ul></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"></ul></span>
<span class="nt"></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li</span> <span class="na">class=</span><span class="s">"expand"</span><span class="nt">><span></span>span 菜单项<span class="nt"></span></span>
<span class="nt"><ul></span>
<span class="nt"><li><span></span>span 菜单项<span class="nt"></span></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"></ul></span>
<span class="nt"></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"></ul></span>
<span class="nt"></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"></ul></span>
<span class="nt"></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"></ul></span>
<span class="nt"></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Link<span class="nt"></a></li></span>
<span class="nt"></ul></span>
<span class="nt"></div></span>
<span class="nt"></body></span>
<span class="nt"></html></span>
既然你这么问了,我就当你是新手了,还好,我也是新手。下面开说:
感觉用select标签效果好像不是很好,效果如下:

首先复习一下基本知识:
display:



代码如下:

希望大神们能批评指正
最后的效果如图:

<span class="cp"><!DOCTYPE html></span>
<span class="nt"><html</span> <span class="na">lang=</span><span class="s">"en"</span><span class="nt">></span>
<span class="nt"><head></span>
<span class="nt"><meta</span> <span class="na">charset=</span><span class="s">"UTF-8"</span><span class="nt">></span>
<span class="nt"><title></span>下拉菜单<span class="nt"></title></span>
<span class="nt"><style </span><span class="na">type=</span><span class="s">"text/css"</span><span class="nt">></span>
<span class="nc">.bt</span><span class="p">{</span>
<span class="k">width</span><span class="o">:</span> <span class="m">50px</span><span class="p">;</span><span class="k">height</span><span class="o">:</span> <span class="m">28px</span><span class="p">;</span>
<span class="k">border</span><span class="o">:</span> <span class="m">1px</span> <span class="k">solid</span> <span class="m">#ddd</span><span class="p">;</span>
<span class="k">background-color</span><span class="o">:</span> <span class="m">#eee</span><span class="p">;</span>
<span class="k">font</span><span class="o">:</span><span class="m">12px</span> <span class="s2">"宋体"</span><span class="p">;</span>
<span class="p">}</span>
<span class="nc">.ct</span><span class="p">{</span>
<span class="k">display</span><span class="o">:</span> <span class="k">none</span><span class="p">;}</span>
<span class="nc">.dt</span><span class="p">{</span>
<span class="k">height</span><span class="o">:</span> <span class="m">30px</span><span class="p">;</span>
<span class="k">margin-top</span><span class="o">:</span> <span class="m">0px</span><span class="p">;</span>
<span class="k">border</span><span class="o">:</span> <span class="m">1px</span> <span class="k">solid</span> <span class="m">#ddd</span><span class="p">;</span>
<span class="k">background-color</span><span class="o">:</span> <span class="nb">white</span><span class="p">;</span>
<span class="k">padding</span><span class="o">:</span><span class="k">auto</span> <span class="m">10px</span><span class="p">;</span>
<span class="p">}</span>
<span class="nc">.dt1</span><span class="p">{</span>
<span class="k">height</span><span class="o">:</span> <span class="m">30px</span><span class="p">;</span>
<span class="k">margin-top</span><span class="o">:</span> <span class="m">1px</span><span class="p">;</span>
<span class="k">border</span><span class="o">:</span> <span class="m">1px</span> <span class="k">solid</span> <span class="m">#ddd</span><span class="p">;</span>
<span class="k">background-color</span><span class="o">:</span> <span class="nb">white</span><span class="p">;</span>
<span class="k">padding</span><span class="o">:</span><span class="k">auto</span> <span class="m">10px</span><span class="p">;}</span>
<span class="nc">.dt</span><span class="nd">:hover</span><span class="o">,</span><span class="nc">.dt1</span><span class="nd">:hover</span><span class="p">{</span><span class="k">background-color</span><span class="o">:</span> <span class="m">#ddd</span><span class="p">;}</span>
<span class="nc">.bt</span><span class="nd">:hover</span><span class="p">{</span><span class="k">background-color</span><span class="o">:</span> <span class="nb">green</span><span class="p">;}</span>
<span class="nc">.at</span><span class="nd">:hover</span> <span class="nc">.ct</span><span class="p">{</span><span class="k">display</span><span class="o">:</span> <span class="k">inline</span><span class="o">-</span><span class="k">block</span><span class="p">;}</span>
<span class="nt"></style></span>
<span class="nt"></head></span>
<span class="nt"><body></span>
<span class="nt"><div</span> <span class="na">class=</span><span class="s">"at"</span><span class="nt">></span>
<span class="nt"><div></span>
<span class="nt"><button</span> <span class="na">class=</span><span class="s">"bt"</span> <span class="na">type=</span><span class="s">"button"</span> <span class="nt">></span>按钮<span class="nt"></button></span>
<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">class=</span><span class="s">"ct"</span> <span class="nt">></span>
<span class="nt"><div</span> <span class="na">class=</span><span class="s">"dt1"</span><span class="nt">></span>下拉菜单<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">class=</span><span class="s">"dt"</span><span class="nt">></span>下拉菜单<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">class=</span><span class="s">"dt"</span><span class="nt">></span>下拉菜单<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">class=</span><span class="s">"dt"</span><span class="nt">></span>下拉菜单<span class="nt"></div></span>
<span class="nt"></div></span>
<span class="nt"></div></span>
<span class="nt"></div></span>
<span class="nt"></body></span>
<span class="nt"></html></span>
要求不高的话用bootstrap 就好了。做这个功能不难,难的是如何封装和复用。
个人看好polymer这种解决方案。
<span class="cp"><!DOCTYPE html></span>
<span class="nt"><html></span>
<span class="nt"><head></span>
<span class="nt"><meta</span> <span class="na">charset=</span><span class="s">"utf-8"</span><span class="nt">></span>
<span class="nt"><title></span>css实现下拉菜单<span class="nt"></title></span>
<span class="nt"><style </span><span class="na">type=</span><span class="s">"text/css"</span><span class="nt">></span>
<span class="o">*</span><span class="p">{</span>
<span class="k">margin</span><span class="o">:</span> <span class="m">0</span><span class="p">;</span>
<span class="k">padding</span><span class="o">:</span> <span class="m">0</span><span class="p">;</span>
<span class="p">}</span>
<span class="nf">#nav</span><span class="p">{</span>
<span class="k">background-color</span><span class="o">:</span> <span class="m">#eee</span><span class="p">;</span>
<span class="k">width</span><span class="o">:</span> <span class="m">300px</span><span class="p">;</span>
<span class="k">height</span><span class="o">:</span> <span class="m">40px</span><span class="p">;</span>
<span class="k">margin</span><span class="o">:</span> <span class="m">0</span> <span class="k">auto</span><span class="p">;</span>
<span class="p">}</span>
<span class="nt">ul</span><span class="p">{</span>
<span class="k">list-style</span><span class="o">:</span> <span class="k">none</span><span class="p">;</span>
<span class="p">}</span>
<span class="nt">ul</span> <span class="nt">li</span> <span class="p">{</span>
<span class="k">float</span><span class="o">:</span> <span class="k">left</span><span class="p">;</span>
<span class="k">line-height</span><span class="o">:</span> <span class="m">40px</span><span class="p">;</span>
<span class="k">text-align</span><span class="o">:</span> <span class="k">center</span><span class="p">;</span>
<span class="p">}</span>
<span class="nt">a</span><span class="p">{</span>
<span class="k">text-decoration</span><span class="o">:</span> <span class="k">none</span><span class="p">;</span>
<span class="k">color</span><span class="o">:</span><span class="m">#000</span><span class="p">;</span>
<span class="k">padding</span><span class="o">:</span> <span class="m">0</span> <span class="m">10px</span><span class="p">;</span>
<span class="k">display</span><span class="o">:</span> <span class="k">block</span><span class="p">;</span>
<span class="p">}</span>
<span class="nt">a</span><span class="nd">:hover</span><span class="p">{</span>
<span class="k">color</span><span class="o">:</span> <span class="m">#fff</span><span class="p">;</span>
<span class="k">background-color</span><span class="o">:</span> <span class="m">#666</span><span class="p">;</span>
<span class="p">}</span>
<span class="nt">ul</span> <span class="nt">li</span> <span class="nt">ul</span> <span class="nt">li</span><span class="p">{</span>
<span class="k">float</span><span class="o">:</span> <span class="k">none</span><span class="p">;</span>
<span class="k">background-color</span><span class="o">:</span> <span class="m">#eee</span><span class="p">;</span>
<span class="k">margin-top</span><span class="o">:</span> <span class="m">2px</span><span class="p">;</span>
<span class="p">}</span>
<span class="nt">ul</span> <span class="nt">li</span> <span class="nt">ul</span> <span class="p">{</span>
<span class="k">position</span><span class="o">:</span> <span class="k">absolute</span><span class="p">;</span>
<span class="k">display</span><span class="o">:</span> <span class="k">none</span><span class="p">;</span>
<span class="p">}</span>
<span class="nt">ul</span> <span class="nt">li</span> <span class="nt">ul</span> <span class="nt">li</span> <span class="nt">a</span><span class="nd">:hover</span><span class="p">{</span>
<span class="k">background-color</span><span class="o">:</span> <span class="m">#06f</span><span class="p">;</span>
<span class="p">}</span>
<span class="nt">ul</span> <span class="nt">li</span><span class="nd">:hover</span> <span class="nt">ul</span><span class="p">{</span>
<span class="k">display</span><span class="o">:</span> <span class="k">block</span><span class="p">;</span>
<span class="p">}</span>
<span class="nt"></style></span>
<span class="nt"></head></span>
<span class="nt"><body></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"nav"</span><span class="nt">></span>
<span class="nt"><ul></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>按钮1<span class="nt"></a></li></span>
<span class="nt"><li></span>
<span class="nt"><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>按钮2<span class="nt"></a></span>
<span class="nt"><ul></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>下拉菜单项<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>下拉菜单项<span class="nt"></a></li></span>
<span class="nt"></ul></span>
<span class="nt"></li></span>
<span class="nt"><li></span>
<span class="nt"><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>按钮3<span class="nt"></a></span>
<span class="nt"><ul></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>下拉菜单项<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>下拉菜单项<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>下拉菜单项<span class="nt"></a></li></span>
<span class="nt"></ul></span>
<span class="nt"></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>按钮4<span class="nt"></a></li></span>
<span class="nt"><li><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>按钮5<span class="nt"></a></li></span>
<span class="nt"></ul></span>
<span class="nt"></div></span>
<span class="nt"></body></span>
<span class="nt"></html></span>
这个是网易云课堂前端微专业的页面布局的期末测试题。
我也试一下。这里大部分答案都是hover事件触发下拉菜单出现。其实我总觉得这样不太自然,所以我尽力去做成(伪)点击触发。
---------------------------------------------------------------------
# 具体想法:
菜单是, 下拉菜单的容器是
然后利用a:focus + .dropdown{ ... } 来实现。
---------------------------------------------------------------------
要点1:CSS如何实现影响其他元素?
看这里 > html - How to affect other elements when a div is hovered
要点2: 如何做出(伪)点击触发?
基本用 a:focus,个人感觉自然一点。当然如果失去焦点,下拉菜单容器也会相应地隐藏。
--------------------------------------------------------------------
# HTML BODY 部分代码:
<span class="nt"><body></span>
<span class="nt"><a</span> <span class="na">href=</span><span class="s">"#"</span><span class="nt">></span>Menu<span class="nt"></a></span>
<span class="nt"><div</span> <span class="na">class=</span><span class="s">"drop-down"</span> <span class="na">id=</span><span class="s">"drop-down"</span><span class="nt">></span>
<span class="nt"><ul></span>
<span class="nt"><li></span>Option 1<span class="nt"></li></span>
<span class="nt"><li></span>Option 2<span class="nt"></li></span>
<span class="nt"><li></span>Option 3<span class="nt"></li></span>
<span class="nt"><li></span>Option 4<span class="nt"></li></span>
<span class="nt"></ul></span>
<span class="nt"></div></span>
<span class="nt"></body></span>
更正一点小错误,只有一个单选按钮时,选中后就不能取消选中了。所以最好用复选按钮。原答案如下
===========================
楼上有同学写了css用伪类:hover实现的下拉菜单 这是一种 我再补充下
下拉菜单抛开样式的不同 交互上无非两种
鼠标移到button上出现菜单(如楼上)
以及点击后出现菜单(我要说的)
题主问的是html+css 而很多同学提到了用js添加click事件 这也是大多数下拉菜单的做法
不过为了不跑题 就只用html+css 不用js 那就考css基本功了
这里简单说下思路
html结构如下
<span class="nt"><button></span>点击我出现下拉菜单<span class="nt"></button></span>
<span class="nt"><input</span> <span class="na">type=</span><span class="s">"checkbok"</span><span class="nt">></span>
<span class="nt"><div></span>
<span class="nt"><ul></span>
<span class="nt"><li></span>XXX<span class="nt"></li></span>
<span class="nt"><li></span>XXX<span class="nt"></li></span>
<span class="nt"><li></span>XXX<span class="nt"></li></span>
<span class="nt"><li></span>XXX<span class="nt"></li></span>
<span class="nt"></ul></span>
<span class="nt"></div></span>
用列表,隐藏,然后hover.的时候block就可以了
http://pepsized.com/css-only-alternative-to-the-select-element/如果想用纯css实现click效果:
http://tympanus.net/codrops/2012/12/17/css-click-events/

H5 verbessert die Erfahrung des Webbenutzers mit Multimedia -Support, Offline -Speicher und Leistungsoptimierung. 1) Multimedia -Unterstützung: H5 und Elemente vereinfachen die Entwicklung und verbessern die Benutzererfahrung. 2) Offline -Speicher: Webstorage und IndexedDB ermöglichen die Verstärkung der Erfahrung offline. 3) Leistungsoptimierung: Webworker und Elemente optimieren die Leistung, um den Bandbreitenverbrauch zu verringern.

Der HTML5 -Code besteht aus Tags, Elementen und Attributen: 1. Das Tag definiert den Inhaltstyp und ist von Winkelklammern umgeben, wie z. 2. Elemente bestehen aus Start -Tags, Inhalten und End -Tags wie Inhalten. 3. Attribute definieren Schlüsselwertpaare im Start-Tag und verbessern Funktionen, z. B.. Dies sind die grundlegenden Einheiten zum Aufbau von Webstruktur.

HTML5 ist eine Schlüsseltechnologie zum Aufbau moderner Webseiten und bietet viele neue Elemente und Funktionen. 1. HTML5 führt semantische Elemente wie usw. ein, die die Webseitenstruktur und die SEO verbessern. 2. Support Multimedia-Elemente und Einbetten von Medien ohne Plug-Ins. 3. Formulare verbessern neue Eingangstypen und Überprüfungseigenschaften und vereinfachen Sie den Überprüfungsprozess. 4. Bieten Sie Offline- und lokale Speicherfunktionen an, um die Leistung der Webseiten und die Benutzererfahrung zu verbessern.

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Webstandards und -technologien haben sich bisher aus HTML4, CSS2 und einfachem JavaScript entwickelt und haben erhebliche Entwicklungen erfahren. 1) HTML5 führt APIs wie Leinwand und Webstorage ein, die die Komplexität und Interaktivität von Webanwendungen verbessern. 2) CSS3 fügt Animations- und Übergangsfunktionen hinzu, um die Seite effektiver zu gestalten. 3) JavaScript verbessert die Entwicklungseffizienz und die Lesbarkeit der Code durch moderne Syntax von Node.js und ES6, wie z. B. Pfeilfunktionen und Klassen. Diese Änderungen haben die Entwicklung von Leistungsoptimierung und Best Practices von Webanwendungen gefördert.

H5 ist nicht nur die Abkürzung von HTML5, sondern auch ein breiteres Ökosystem der modernen Webentwicklungstechnologie: 1. H5 enthält HTML5, CSS3, JavaScript und verwandte APIs und Technologien; 2. Es bietet eine reichhaltigere, interaktive und reibungslose Benutzererfahrung und kann nahtlos auf mehreren Geräten ausgeführt werden. 3. Mit dem H5 -Technologie -Stack können Sie reaktionsschnelle Webseiten und komplexe interaktive Funktionen erstellen.

H5 und HTML5 beziehen sich auf dasselbe, nämlich HTML5. HTML5 ist die fünfte Version von HTML, die neue Funktionen wie semantische Tags, Multimedia -Support, Leinwand und Grafiken, Offline -Speicher und lokaler Speicher bietet, die Ausdrucksfähigkeit und Interaktivität von Webseiten verbessert.

H5REFERSTOHTML5, ApivotaltechnologyInwebdevelopment.1) HTML5IntroducesNewelementsandapisrich, Dynamicwebapplications.2) ITSUPP ortsmultimediaWitHoutPlugins, BETHINGINGUSEREXPERICERCROSSDEVICES.3) SEMANTICELEMENTSIMPROVEPENTENTENTENTRUCTENTRUCTELUREANDSEO.4) H5'SRespo


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