JSFiddle - React, Tailwind, and code Playground

by chintsu

HTML

<body>
    <span class="st-scroll-up">up</span>
    <ul id="ul">
        
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
        <li>6</li>
        <li>7</li>
        <li>8</li>
        <li>9</li>
        <li>10</li>
        <li>11</li>
        <li>12</li>
        <li>13</li>
        <li>14</li>
        <li>15</li>
        <li>16</li>
        <li>17</li>
        <li>18</li>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
        <li>6</li>
        <li>7</li>
        <li>8</li>
        <li>9</li>
        <li>10</li>
        <li>11</li>
        <li>12</li>
        <li>13</li>
        <li>14</li>
        <li>15</li>
        <li>16</li>
        <li>17</li>
        <li>18</li>
    </ul>
    <span class="st-scroll-down">down</span>
    <hr>
    
    <label for="scrollTop">scrollTop: <span id="scrollTop">0</span></label>
    <span id="scrollTop2"></span>
    <label for="scrollHeight">scrollHeight: <span id="scrollHeight"></span></label>
    <label for="outerHeight">outerHeight: <span id="outerHeight"></span></label> 
    <label for="offsetTop">offsetTop: <span id="offsetTop"></span></label>
    <label for="clientHeight">clientHeight: <span id="clientHeight"></span></label>
    <label for="scrollHeight-offsetTop">scrollHeight-clientHeight: <span id="scrollHeight-clientHeight"></span>
    <label for="scrollTime">scrollTime: <span id="scrollTime"></span>
</body>

CSS

ul { max-height: 5em; overflow: hidden; position: relative}

li { border: solid 1px #50c900; padding: 3px }
label {display: block}

JavaScript

(function($) {

var types = ['DOMMouseScroll', 'mousewheel'];

if ($.event.fixHooks) {
    for ( var i=types.length; i; ) {
        $.event.fixHooks[ types[--i] ] = $.event.mouseHooks;
    }
}

$.event.special.mousewheel = {
    setup: function() {
        if ( this.addEventListener ) {
            for ( var i=types.length; i; ) {
                this.addEventListener( types[--i], handler, false );
            }
        } else {
            this.onmousewheel = handler;
        }
    },
    
    teardown: function() {
        if ( this.removeEventListener ) {
            for ( var i=types.length; i; ) {
                this.removeEventListener( types[--i], handler, false );
            }
        } else {
            this.onmousewheel = null;
        }
    }
};

$.fn.extend({
    mousewheel: function(fn) {
        return fn ? this.bind("mousewheel", fn) : this.trigger("mousewheel");
    },
    
    unmousewheel: function(fn) {
        return this.unbind("mousewheel", fn);
    }
});


function handler(event) {
    var orgEvent = event || window.event, args = [].slice.call( arguments, 1 ), delta = 0, returnValue = true, deltaX = 0, deltaY = 0;
    event = $.event.fix(orgEvent);
    event.type = "mousewheel";
    
    // Old school scrollwheel delta
    if ( orgEvent.wheelDelta ) { delta = orgEvent.wheelDelta/120; }
    if ( orgEvent.detail ) { delta = -orgEvent.detail/3; }
    
    // New school multidimensional scroll (touchpads) deltas
    deltaY = delta;
    
    // Gecko
    if ( orgEvent.axis !== undefined && orgEvent.axis === orgEvent.HORIZONTAL_AXIS ) {
        deltaY = 0;
        deltaX = -1*delta;
    }
    
    // Webkit
    if ( orgEvent.wheelDeltaY !== undefined ) { deltaY = orgEvent.wheelDeltaY/120; }
    if ( orgEvent.wheelDeltaX !== undefined ) { deltaX = -1*orgEvent.wheelDeltaX/120; }
    
    // Add event and delta to the front of the arguments
    args.unshift(event, delta, deltaX, deltaY);
    
    return ($.event.dispatch ||...