javascript中的曲线球轨迹

Question

我有一个JavaScript函数，我写了一个红色的css球在屏幕上随机移动。问题是，因为它直接从一个位置到另一个位置，所以看起来并不那么平滑。当它改变位置时使它做曲线可能会使这更顺畅。基于提供的代码，这样做的好方法是什么？

$('#menu_button4').click(function(){
    $('#ball').show();
    cake = function(a,b,u) {return (1-u) * a + u * b;};
    draw_pos = function(element, property1, property2, start, end, duration) {
      var interval = 10;
      var steps = duration/interval;
      var step_u = 1.0/steps;
      var u = 0.0;
      var theInterval = setInterval(function(){
        if (u >= 1.0){ clearInterval(theInterval) }
        var s = parseInt(cake(start.s, end.s, u));
        var d = parseInt(cake(start.d, end.d, u));
        var x_pos = s+'%';
        var y_pos = d+'%';
        el.style.setProperty(property1, x_pos);
        el.style.setProperty(property2, y_pos);
        u += step_u;
      }, interval);
    };
    el = document.getElementById('ball');
    property1 = 'top';
    property2 = 'left';
    startdeg_1 = {s:'0', d:'0'};
    enddeg_1 = {s:Math.floor((Math.random()*100)+1), d:Math.floor((Math.random()*100)+1)};
    enddeg_2 = {s:Math.floor((Math.random()*100)+1), d:Math.floor((Math.random()*100)+1)};
    enddeg_3 = {s:Math.floor((Math.random()*100)+1), d:Math.floor((Math.random()*100)+1)};
    enddeg_4 = {s:Math.floor((Math.random()*100)+1), d:Math.floor((Math.random()*100)+1)};
    enddeg_5 = {s:'40', d:'25'};
    enddeg_6 = {s:'20', d:'20'};
    draw_pos(el, property1, property2, startdeg_1, enddeg_1, 80);
    setTimeout(function(){draw_pos(el, property1, property2, enddeg_1, enddeg_2, 80)}, 700);
    setTimeout(function(){draw_pos(el, property1, property2, enddeg_2, enddeg_3, 80)}, 1400);
    setTimeout(function(){draw_pos(el, property1, property2, enddeg_3, enddeg_4, 80)}, 2050);
    setTimeout(function(){draw_pos(el, property1, property2, enddeg_4, enddeg_5, 80)}, 2650);
    setTimeout(function(){draw_pos(el, property1, property2, enddeg_5, enddeg_6, 80)}, 3200);
  });