动态 javascript 滚动未按预期工作

Dynamic javascript scroll not working as intended

所以我一直在尝试做一个动态的滚动动画,它反复上下滚动,但是一旦鼠标进入网页的主体就可以停止,然后当光标离开上述时重新启动div,如果用户自己滚动,以及内容量是否发生变化,它将计算在内

但它所做的只是正确地启动第一个动画,然后放弃停在底部拒绝让用户滚动。

当我尝试触发停止功能时,它只是给我错误 "TypeError: animate(...) is undefined, can't access property 0 of it",我不知道为什么。

有什么想法吗?

setTimeout(function(){

    if(screen.width >= 1300 && $('#animatediv')[0].scrollHeight > 700){

        var screenview = document.getElementById('animatediv').clientHeight;
        var to = $('#animatediv')[0].scrollHeight;
        var animatetime = ((to - 700) * 800) / 80;
        var used = 0;
        var delay = 2000;
        var userscroll = 0;
        var animatescroll = 0;
        var running = 0;

        $('#main').mouseleave(function() {
            running = 1;
            userscroll = $('#animatediv').scrollTop();
            setTimeout(function(){animate(screenview, to, animatetime, used, delay, userscroll, animatescroll, running)}, delay);
        });


        $('#main').mouseenter(function() {
            running = 0;
            var news = animate(screenview, to, animatetime, used, delay, userscroll, animatescroll, running)
            used = news[0];
            to = news[1];
            $('#animatediv').stop();
            animatescroll = $('#animatediv').scrollTop();
        });

    }

}, 600);




function animate(screenview, to, animatetime, used, delay, userscroll, animatescroll, running){

    to = $('#animatediv')[0].scrollHeight;

    var time = (animatetime - used) + (animatescroll - userscroll);

    if(to != 0){
        animateto = to - screenview;
    }
    else{
        animateto = 0;
    }

    $('#animatediv').animate({ scrollTop: animateto}, time, 'linear');

    setInterval(function(){

        if(running == 0){
            var returns = [used, to]
            return returns;
        }
        if(used == animatetime){
            if(to != 0){
                to = 0;
            }
            else{
                to = $('#animatediv')[0].scrollHeight;
            }
            used = 0;
            setTimeout(function(){animate(screenview, to, animatetime, used, delay, userscroll, animatescroll)}, delay);
        }
        else{
            used++;
        }

    }, 1);

}

错误太多。所以我做了一个不同的。这是 Jsfiddle

   var runnig=true, deriction = "down";
   var time = 3000, lastScrollTop = 0;
   animate($('#animatediv')[0]);
   $('#main').mouseleave(function() {
         removeAndAnimate();
  });
   $('#main').mouseenter(function() {
        runnig = false;
        lastScrollTop = $('#animatediv')[0].scrollTop;
        if(deriction === "down"){
          deriction = "up";
        }else{
          deriction = "down";
        }
        
        $('#animatediv').stop(true);
        setTimeout(function(){
           $('#animatediv')[0].addEventListener("scroll", userScroll, false);
        }, 100);
        
  });



async function removeAndAnimate(){
  var resultat = await ($('#animatediv')[0].removeEventListener("scroll", userScroll, false));
  runnig = true;
  animate($('#animatediv')[0]);
}



function userScroll(){
   var st = this.scrollTop; 
   if (st > lastScrollTop){
      deriction = "down";
   } else {
      deriction = "up";
   }
   lastScrollTop = st <= 0 ? 0 : st;
}
 
 function animate(element){
  
  var scrollTop = element.scrollTop;
    var heightToScroll = element.scrollHeight - $(element).height();
  var animateto = 0, delay = 0;
  if(scrollTop != 0){
      if(deriction === "down"){
        animateto = heightToScroll;
        delay = (heightToScroll - scrollTop)*time/heightToScroll;
      }else{
        delay = scrollTop*time/heightToScroll;
      }
  }else{
      animateto = heightToScroll;
      delay = time;
    }

    
    if(deriction === "down"){
      deriction = "up";
    }else{
      deriction = "down"
    }
  
  $('#animatediv').animate({ scrollTop: animateto}, delay, 'linear', function(){
      if(runnig){
        animate(element);
      }
    });
  
 }
*{
 font-size: 62,5%;
 margin: 0;
 padding: 0;
}

body{
 background-color: #F5E7D3;
}

#main{
 width: 90%;
 margin: auto;
 text-align: center;
 background: linear-gradient(to bottom, #FFF1C4 20%, #72982D);
 /* overflow: hidden; */
 height: 350px;
}

#animatediv{
  border: 1px solid black;
 width: 50%;
 float: right;
 height: 300px;
 overflow-y: auto;
 overflow-x: hidden;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id='main'>
  <div id='animatediv'>
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    <br />
  </div>
</div>