SmoothWheel Javascript. Reference : https://codepen.io/xtianmiller/pen/oGEWQj

smoothWheel.js

    (function($){
        var self=this,
            container,
            running=!1,
            currentY=0,
            targetY=0,
            oldY=0,
            maxScrollTop=0,
            minScrollTop,
            direction,
            onRenderCallback=null,
            fricton=0.90,
            vy=0,
            stepAmt=1,
            minMovement=0.1,
            ts=0.1;
        var updateScrollTarget=function(amt){targetY+=amt;vy+=(targetY-oldY)*stepAmt;oldY=targetY}
        var render=function(){if(vy<-(minMovement)||vy>minMovement){currentY=(currentY+vy);if(currentY>maxScrollTop){currentY=vy=0}else if(currentY<minScrollTop){vy=0;currentY=minScrollTop}
            container.scrollTop(-currentY);vy*=fricton;if(onRenderCallback){onRenderCallback()}}}
        var animateLoop=function(){if(!running)return;requestAnimFrame(animateLoop);render()}
        var onWheel=function(e){e.preventDefault();var evt=e.originalEvent;var delta=evt.detail?evt.detail*-1:evt.wheelDelta/40;var dir=delta<0?-1:1;if(dir!=direction){vy=0;direction=dir}
            currentY=-container.scrollTop();updateScrollTarget(delta)}
        window.requestAnimFrame=(function(){return window.requestAnimationFrame||window.webkitRequestAnimationFrame||window.mozRequestAnimationFrame||window.oRequestAnimationFrame||window.msRequestAnimationFrame||function(callback){window.setTimeout(callback,1000/60)}})();var normalizeWheelDelta=function(){var distribution=[],done=null,scale=30;return function(n){if(n==0)return n;if(done!=null)return n*done;var abs=Math.abs(n);outer:do{for(var i=0;i<distribution.length;++i){if(abs<=distribution[i]){distribution.splice(i,0,abs);break outer}}
            distribution.push(abs)}while(!1);var factor=scale/distribution[Math.floor(distribution.length/3)];if(distribution.length==500)done=factor;return n*factor}}();$.fn.smoothWheel=function(){var options=jQuery.extend({},arguments[0]);return this.each(function(index,elm){if(!('ontouchstart' in window)){container=$(this);container.bind("mousewheel",onWheel);container.bind("DOMMouseScroll",onWheel);targetY=oldY=container.scrollTop();currentY=-targetY;minScrollTop=container.get(0).clientHeight-container.get(0).scrollHeight;if(options.onRender){onRenderCallback=options.onRender}
            if(options.remove){log("122","smoothWheel","remove","");running=!1;container.unbind("mousewheel",onWheel);container.unbind("DOMMouseScroll",onWheel)}else if(!running){running=!0;animateLoop()}}})}})(jQuery)
            $(document).ready(function(){$(window).smoothWheel();});