js代码

<script src="js/jquery.min.js"></script>
<script src="js/resize.js" type="text/javascript" charset="utf-8"></script>
<script type="text/javascript">
	$(function(){
		
	var posT = $(".header").height()+$(".banner_one").height();
 	var overstepT = $(".term").height();
 	var heigtPt = overstepT-$(".term_nav").height();
 	
	var domH = $(".term_nav li").height();
	var domY,moveY,index,item_top;
	$(".term_nav").on({
        touchstart: function (e) {
            startY = e.originalEvent.targetTouches[0].pageY;
        },
        touchmove: function (e) {  
        	e.preventDefault();          
            $("body").on({
                touchmove: function (e) {
                    e.preventDefault();
                }
            });
            domY = $(this).offset().top;
            moveY = e.originalEvent.targetTouches[0].pageY;
			index = parseInt((moveY-domY)/domH);
			$(".term_nav li").eq(index).addClass("on").siblings().removeClass("on");
        
			item_top=$('.term_box').eq(index).offset().top-100;
			$(window).scrollTop(item_top);
        },
        touchend: function () {
        	$("body").off("touchmove")
        }
 	});
 	$(".term_nav li").click(function(){
 		$(this).addClass("on").siblings().removeClass("on");
 		item_top = $('.term_box').eq($(this).index()).offset().top-100;
 		$(window).scrollTop(item_top)
 	})
 	
   	$(window).scroll(function(){
   		
   		if($(window).scrollTop()<=posT){
   			console.log("1")
   			$(".term_nav").css({
   				"position":"absolute",
   				"top":"0.3rem",
   				"transform": "translateY(0)",
   			})
   		}
   		else if(posT<$(window).scrollTop()){
   			console.log("2")
   			$(".term_nav").css({
   				"position":"fixed",
   				"top":"50%",
   				"transform": "translateY(-50%)",
   			})

   		}
   		$('.term_box').each(function(){
            var $details_item_top=$('.term_box').eq($(this).index()).offset().top;
            var cs = $(".term_box").eq($(this).index()).height();
            console.log($details_item_top+" "+$(window).scrollTop())
            if($details_item_top+cs-100>$(window).scrollTop()){
                $('.term_nav li').removeClass('on');
                $('.term_nav li').eq($(this).index()).addClass('on');
                return false;
            }
        });

   	})
 	
 	})
</script>