滚动监听导航 JQUERY 易懂

非常易懂一看明白，留着

// 滚动监听$('#detail-tab span').on('click', function(){var i = $(this).attr('rel');var boxTop = $('#'+i).offset().top - 49;$('#detail-tab span').removeClass('on');$(this).addClass('on');window.scrollTo(0, boxTop);$('#detail-tab').animate({'position':'fixed', 'top':0},300);});var oneTop = $('#detail-tab').offset().top;$(window).scroll(function(){var leftNav = $('#detail-tab span'),docTop = $(document).scrollTop();if(docTop >= oneTop){$('#detail-tab').css({'position':'fixed', 'top':0});$('.nr_list').each(function(index, domEle){var uhTop = $(domEle).offset().top-49,uhBot = uhTop + $(domEle).height();if(docTop<uhBot && docTop>=uhTop){$('#detail-tab span').removeClass('on');$('#detail-tab span:eq('+ index +')').addClass('on');}else{return;}})}else{$('#detail-tab').css({'position':'static'});}})