原生JS代码封装（抛物线运动）

function parabola(ele, stop){

        

        //y == a*x^2 + bx + c

        //原点

        var centerpoint = {

            x : ele.offsetLeft,

            y : ele.offsetTop

        }

        //目标点的 相对坐标系位置

        var target = {

            x : stop.offsetLeft - centerpoint.x,

            y : centerpoint.y - stop.offsetTop

        }

        //系数

        var a = -0.0015;

        // b = (y - ax^2)/x

        b = (target.y - a*target.x*target.x)/target.x;

        

        var _x = 0;

        var t = setInterval(function(){

            _x+=8;

            var _y = a*_x*_x + b*_x;

            ele.style.left = _x + centerpoint.x + "px";

            ele.style.top = centerpoint.y - _y + "px";

            

            if(_x >= target.x) {

                ele.style.left = stop.offsetLeft + "px";

                ele.style.top = stop.offsetTop + "px";

                clearInterval(t)

            }

        }, 20);

    }