jquery implementiert ein einfaches sekundäres Navigations-Dropdown-Menü effect

Das Beispiel in diesem Artikel beschreibt, wie JQuery einen einfachen Dropdown-Menüeffekt für die sekundäre Navigation implementiert. Teilen Sie es als Referenz mit allen. Die Details lauten wie folgt:

Der durch jQuery-Code implementierte sekundäre Navigationsmenüeffekt ist sehr einfach. Freunde, die einen einfachen Stil mögen, können ihn herunterladen. Das Menü unterstützt bis zu zwei Ebenen, und die Zusammenarbeit von CSS ist auch sehr wichtig. Ich werde nicht näher darauf eingehen. Wenn Sie den Code möchten, kopieren Sie ihn einfach.

Der Screenshot des Laufeffekts sieht wie folgt aus:

Die Online-Demo-Adresse lautet wie folgt:

http://demo.jb51.net/js/2015/jquery-2jxl-menu-codes/

Der spezifische Code lautet wie folgt:

<title>jquery二级导航菜单</title>
<style>
.ddsmoothmenu {
 MARGIN: 0px auto; FONT: 12px Verdana; WIDTH: 730px
}
.ddsmoothmenu UL {
 PADDING-RIGHT: 0px; PADDING-LEFT: 0px;BACKGROUND: #2b9801; Z-INDEX: 100; FLOAT: left; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px; LIST-STYLE-TYPE: none
}
.ddsmoothmenu UL LI {
 DISPLAY: block; FLOAT: left; WIDTH: 81px; LINE-HEIGHT: 31px; POSITION: relative; TEXT-ALIGN: center
}
 HTML .ddsmoothmenu UL LI {
 FLOAT: left; WIDTH: 81px; LINE-HEIGHT: 31px; POSITION: relative; TEXT-ALIGN: center
}
.ddsmoothmenu UL LI A {
 DISPLAY: block; FONT-WEIGHT: bold; WIDTH: 81px; TEXT-DECORATION: none
}
.ddsmoothmenu UL LI A:link {
 COLOR: #fff
}
.ddsmoothmenu UL LI A:visited {
 COLOR: #fff
}
.ddsmoothmenu UL LI A:hover {
 COLOR: #ffff00
}
.ddsmoothmenu UL LI UL {
 LEFT: 0px; VISIBILITY: hidden; POSITION: absolute
}
.ddsmoothmenu UL LI UL LI {
 BACKGROUND: #2b9801; FLOAT: left; WIDTH: 81px; LINE-HEIGHT: 25px; BORDER-BOTTOM: #96d47d 1px solid
}
.ddsmoothmenu UL LI UL LI A {
 DISPLAY: block; WIDTH: 81px; TEXT-DECORATION: none
}
.ddsmoothmenu UL LI UL LI A:hover {
 BACKGROUND: #51b228
}
.ddsmoothmenu UL LI UL LI UL {
 TOP: 0px
}
.downarrowclass {
 DISPLAY: none; POSITION: absolute
}
.rightarrowclass {
 DISPLAY: none; POSITION: absolute
}
.ddshadow {
 BACKGROUND: silver; LEFT: 0px; WIDTH: 0px; POSITION: absolute; TOP: 0px; HEIGHT: 0px
}
.toplevelshadow {
 opacity: 0.8
}
</style>
<SCRIPT src="jquery1.3.2.js" type=text/javascript></SCRIPT>
<SCRIPT type=text/javascript>
var ddsmoothmenu={
//Specify full URL to down and right arrow images (23 is padding-right added to top level LIs with drop downs):
arrowimages: {down:['downarrowclass', '', 0], right:['rightarrowclass', '']},
transition: {overtime:300, outtime:300}, //duration of slide in/ out animation, in milliseconds
shadow: {enabled:false, offsetx:5, offsety:5},
detectwebkit: navigator.userAgent.toLowerCase().indexOf("applewebkit")!=-1, //detect WebKit browsers (Safari, Chrome etc)
getajaxmenu:function($, setting){ //function to fetch external page containing the panel DIVs
 var $menucontainer=$('#'+setting.contentsource[0]) //reference empty div on page that will hold menu
 $menucontainer.html("Loading Menu...")
 $.ajax({
  url: setting.contentsource[1], //path to external menu file
  async: true,
  error:function(ajaxrequest){
   $menucontainer.html('Error fetching content. Server Response: '+ajaxrequest.responseText)
  },
  success:function(content){
   $menucontainer.html(content)
   ddsmoothmenu.buildmenu($, setting)
  }
 })
},
buildshadow:function($, $subul){
},
buildmenu:function($, setting){
 var smoothmenu=ddsmoothmenu
 var $mainmenu=$("#"+setting.mainmenuid+">ul") //reference main menu UL
 var $headers=$mainmenu.find("ul").parent()
 $headers.each(function(i){
  var $curobj=$(this).css({zIndex: 100-i}) //reference current LI header
  var $subul=$(this).find('ul:eq(0)').css({display:'block'})
  this._dimensions={w:this.offsetWidth, h:this.offsetHeight, subulw:$subul.outerWidth(), subulh:$subul.outerHeight()}
  this.istopheader=$curobj.parents("ul").length==1&#63; true : false //is top level header&#63;
  $subul.css({top:this.istopheader&#63; this._dimensions.h+"px" : 0})
  $curobj.children("a:eq(0)").css(this.istopheader&#63; {paddingRight: smoothmenu.arrowimages.down[2]} : {}).append( //add arrow images
   '<img src="'+ (this.istopheader&#63; smoothmenu.arrowimages.down[1] : smoothmenu.arrowimages.right[1])
   +'" class="' + (this.istopheader&#63; smoothmenu.arrowimages.down[0] : smoothmenu.arrowimages.right[0])
   + '" style="border:0;" />'
  )
  if (smoothmenu.shadow.enabled){
   this._shadowoffset={x:(this.istopheader&#63;$subul.offset().left+smoothmenu.shadow.offsetx : this._dimensions.w), y:(this.istopheader&#63; $subul.offset().top+smoothmenu.shadow.offsety : $curobj.position().top)} //store this shadow's offsets
   if (this.istopheader)
    $parentshadow=$(document.body)
   else{
    var $parentLi=$curobj.parents("li:eq(0)")
    $parentshadow=$parentLi.get(0).$shadow
   }
   this.$shadow=$('<div class="ddshadow'+(this.istopheader&#63; ' toplevelshadow' : '')+'"></div>').prependTo($parentshadow).css({left:this._shadowoffset.x+'px', top:this._shadowoffset.y+'px'}) //insert shadow DIV and set it to parent node for the next shadow div
  }
  $curobj.hover(
   function(e){
    var $targetul=$(this).children("ul:eq(0)")
    this._offsets={left:$(this).offset().left, top:$(this).offset().top}
    var menuleft=this.istopheader&#63; 0 : this._dimensions.w
    menuleft=(this._offsets.left+menuleft+this._dimensions.subulw>$(window).width())&#63; (this.istopheader&#63; -this._dimensions.subulw+this._dimensions.w : -this._dimensions.w) : menuleft //calculate this sub menu's offsets from its parent
    if ($targetul.queue().length<=1){ //if 1 or less queued animations
     $targetul.css({left:menuleft+"px", width:this._dimensions.subulw+'px'}).animate({height:'show',opacity:'show'}, ddsmoothmenu.transition.overtime)
     if (smoothmenu.shadow.enabled){
      var shadowleft=this.istopheader&#63; $targetul.offset().left+ddsmoothmenu.shadow.offsetx : menuleft
      var shadowtop=this.istopheader&#63;$targetul.offset().top+smoothmenu.shadow.offsety : this._shadowoffset.y
      if (!this.istopheader && ddsmoothmenu.detectwebkit){ //in WebKit browsers, restore shadow's opacity to full
       this.$shadow.css({opacity:1})
      }
      this.$shadow.css({overflow:'', width:this._dimensions.subulw+'px', left:shadowleft+'px', top:shadowtop+'px'}).animate({height:this._dimensions.subulh+'px'}, ddsmoothmenu.transition.overtime)
     }
    }
   },
   function(e){
    var $targetul=$(this).children("ul:eq(0)")
    $targetul.animate({height:'hide', opacity:'hide'}, ddsmoothmenu.transition.outtime)
    if (smoothmenu.shadow.enabled){
     if (ddsmoothmenu.detectwebkit){ //in WebKit browsers, set first child shadow's opacity to 0, as "overflow:hidden" doesn't work in them
      this.$shadow.children('div:eq(0)').css({opacity:0})
     }
     this.$shadow.css({overflow:'hidden'}).animate({height:0}, ddsmoothmenu.transition.outtime)
    }
   }
  ) //end hover
 }) //end $headers.each()
 $mainmenu.find("ul").css({display:'none', visibility:'visible'})
},
init:function(setting){
 if (typeof setting.customtheme=="object" && setting.customtheme.length==2){
  var mainmenuid='#'+setting.mainmenuid
  document.write('<style type="text/css">\n'
   +mainmenuid+', '+mainmenuid+' ul li a {background:'+setting.customtheme[0]+';}\n'
   +mainmenuid+' ul li a:hover {background:'+setting.customtheme[1]+';}\n'
  +'</style>')
 }
 jQuery(document).ready(function($){ //override default menu colors (default/hover) with custom set&#63;
  if (typeof setting.contentsource=="object"){ //if external ajax menu
   ddsmoothmenu.getajaxmenu($, setting)
  }
  else{ //else if markup menu
   ddsmoothmenu.buildmenu($, setting)
  }
 })
}
} //end ddsmoothmenu variable
//Initialize Menu instance(s):
ddsmoothmenu.init({
 mainmenuid: "smoothmenu1", //menu DIV id
 customtheme: [], //override default menu CSS background values&#63; Uncomment: ["normal_background", "hover_background"]
 contentsource: "markup" //"markup" or ["container_id", "path_to_menu_file"]
})
</SCRIPT>
<DIV class=ddsmoothmenu id=smoothmenu1>
<UL>
 <LI><A href="#">首页</A> 
 </LI>
 <LI><A href="#">一年级</A> 
 <UL>
 <LI><A href="#">一年级1班</A> </LI>
 <LI><A href="#">一年级2班</A> </LI>
 <LI><A href="#">一年级3班</A> </LI>
 <LI><A href="#">一年级4班</A> </LI>
 <LI><A href="#">一年级5班</A> 
 </LI></UL></LI>
 <LI><A href="#">二年级</A> 
 <UL>
 <LI><A href="#">二年级1班</A> </LI>
 <LI><A href="#">二年级2班</A> </LI>
 <LI><A href="#">二年级3班</A> </LI>
 <LI><A href="#">二年级4班</A> </LI>
 <LI><A href="#">二年级5班</A> 
 </LI></UL></LI>
 <LI><A href="#">三年级</A> 
 <UL>
 <LI><A href="#">三年级1班</A> </LI>
 <LI><A href="#">三年级2班</A> </LI>
 <LI><A href="#">三年级3班</A> </LI>
 <LI><A href="#">三年级4班</A> </LI>
 <LI><A href="#">三年级5班</A> 
 </LI></UL></LI>
<LI><A href="#">四年级</A> 
 <UL>
 <LI><A href="#">四年级1班</A> </LI>
 <LI><A href="#">四年级2班</A> </LI>
 <LI><A href="#">四年级3班</A> </LI>
 <LI><A href="#">四年级4班</A> </LI>
 <LI><A href="#">四年级5班</A> 
 </LI></UL></LI>
 <LI><A href="#">五年级</A> 
 <UL>
 <LI><A href="#">五年级1班</A> </LI>
 <LI><A href="#">五年级2班</A> </LI>
 <LI><A href="#">五年级3班</A> </LI>
 <LI><A href="#">五年级4班</A> </LI>
 <LI><A href="#">五年级5班</A> 
 </LI></UL></LI>
 <LI><A href="#">六年级</A> 
 <UL>
 <LI><A href="#">六年级1班</A> </LI>
 <LI><A href="#">六年级2班</A> </LI>
 <LI><A href="#">六年级3班</A> </LI>
 <LI><A href="#">六年级4班</A> </LI>
 <LI><A href="#">六年级5班</A> 
 </LI></UL></LI>
 <LI><A href="#">七年级</A> 
 <UL>
 <LI><A href="#">七年级1班</A> </LI>
 <LI><A href="#">七年级2班</A> </LI>
 <LI><A href="#">七年级3班</A> </LI>
 <LI><A href="#">七年级4班</A> </LI>
 <LI><A href="#">七年级5班</A> 
 </LI></UL></LI>
</UL>
</DIV>

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Ich hoffe, dass dieser Artikel für das JQuery-Programmierungsdesign aller hilfreich sein wird.