jquery implements fixed top positioning scrolling navigation effect code

jquery implements fixed top positioning scrolling navigation effect code, very common effect, very practical; when scrolling the scroll bar, the navigation is fixed on the top, and when scrolling to the corresponding plate, the current navigation is highlighted, and when the navigation text is clicked, smooth jumps to the corresponding plate.

$( function (){           var subNav_active = $( ".adv_active" );          var subNav_scroll =  function (target){              subNav_active.removeClass   ( "adv_active" );              target.parent().addClass( "adv_active" );              subNav_active = target.parent();          };          $( "#subNav a" ).click( function (){              subNav_scroll($( this ));              var target = $( this ).attr( "href" );              var targetScroll = $(target).offset().top - 80;              $( "html,body" ).animate({scrollTop:targetScroll},300);              return false ;          });          //页面跳转时定位          if (window.location.hash){              var targetScroll = $(window.location.hash).offset().top - 80;              $( "html,body" ).animate({scrollTop:targetScroll},300);          }          $(window).scroll( function (){              var $ this = $( this );              var targetTop = $( this ).scrollTop();              var footerTop = $( "#footer" ).offset().top;              var height = $(window).height();              if (targetTop >= 520){                  $( "#subNav" ).addClass( "fixedSubNav" );                  $( ".empty-placeholder" ).removeClass( "hidden" );              } else {                  $( "#subNav" ).removeClass( "fixedSubNav" );                  $( ".empty-placeholder" ).addClass( "hidden" );              }              if (targetTop < 750){                  subNav_scroll($( ".adv_door" ));              } else if (targetTop > 1200 && targetTop < 1640){                      subNav_scroll($( ".adv_source" ));              } else if (targetTop > 2314 && targetTop < 2734){                      subNav_scroll($( ".adv_price" ));              } else if (targetTop > 2968 && targetTop < 3268){                      subNav_scroll($( ".adv_transfer" ));              } else if (targetTop > 3327 && targetTop < 3627){                      subNav_scroll($( ".adv_payment" ));              } else if (targetTop > 3651 && targetTop < 4071){                      subNav_scroll($( ".adv_promise" ));              } else if (targetTop > 4163 && targetTop < 4473){                      subNav_scroll($( ".adv_ride" ));              } else if (targetTop > 4580){                  subNav_scroll($( ".adv_finance" ));              }          })    }());

jquery implements fixed top positioning scrolling navigation effect code