[Jquery]导航菜单效果-纵向

浏览数：21 / 时间：2015年06月09日

$( document ).ready( function(e){

   var $catCont = $( ".cat-cont" );    //二级菜单div
   var $catList = $( ".J_Cat" );       //一级菜单li

   $catList.on( "mouseenter", function(){

       var index = $( this ).index();
       var $curCatList = $( ".cat-cont-bd>li:eq(" + index + ")" );         //鼠标移上去对应的二级菜单的li

       $catList.removeClass( "selected selected-prev" );

       $( this ).addClass( "selected" ).prev().addClass( "selected-prev" );

       $catCont.show();

       $curCatList.css( "display", "list-item").siblings().css( "display", "none" );

       var viewHeight = $( window ).height();
       var catOffsetTop = $( this ).offset().top - $( window ).scrollTop();
       var catBottomGap = viewHeight - catOffsetTop;

       var catPositionTop = $( this ).position().top;

       var catContHeight = $catCont.height();

       if( catBottomGap >= catContHeight ) {
           $catCont.css( "top", catPositionTop );
       }
       if( catBottomGap < catContHeight && viewHeight >= catContHeight ) {
           $catCont.css( "top", catPositionTop - ( catContHeight - catBottomGap ) - 20 );
       }
       if( catBottomGap < catContHeight && viewHeight < catContHeight ) {
           $catCont.css( "top", catPositionTop );
       }
       if( catBottomGap <= 66 ) {
           $catCont.css( "top", catPositionTop - catContHeight + 33 );
       }

   }).on( "mouseleave", function( event ){
       if( !$( event.relatedTarget ).hasClass( "cat-cont-bd" ) ){    //交互灾难:离开一级菜单划不到二级菜单，如何知道离开一级菜单后进入的是二级菜单？jquery提供属性：event.relatedTarget(离开后进入的对象)
           $( this ).removeClass( "selected selected-prev" );
           $catCont.hide();
       }
   });

   $catCont.on( "mouseleave", function(){
       $catCont.hide();
       $catList.removeClass( "selected selected-prev" );
   });
});