We Keep Coding

jquery plugin, settimeout and div not being append, simple weird case

I'm writing a jquery plugin the code below is not working (I mean the setTimeout is working but nothing is append)
var self = this;
for (var i=0; i<=10; i++) {
setTimeout(function() {
self.append(bubble);
}, 1000);
}
And the code below is working:
for (var i=0; i<=10; i++) {
this.append(bubble);
}
this is a jquery selection. I really don't get what's going on. It can't be scope issue .. can it be ? I don't get it. Thanks in advance for you help
Edit: bubble is a simple div (" ")
Below the whole plugin code:
(function($) {
'use strict';
$.fn.randomBubble = function(options) {
var self = this;
var settings = $.extend({
color: 'blue',
backgroundColor: 'white',
maxBubbleSize: 100
}, options);
var frame = {
height: this.height(),
width: this.width(),
}
var bubble = "<div class='randomBubble'> </div>";
this.getLeft = function(width) {
var left = Math.random() * frame.width;
if (left > (frame.width / 2)) {
left -= width;
} else {
left += width;
}
return left
}
this.getTop = function(height) {
var top = Math.random() * frame.height;
if (top > (frame.height / 2)) {
top -= height;
} else {
top += height;
}
return top
}
this.removeBubbles = function() {
var currentBubbles = this.find('.randomBubble');
if (currentBubbles.length) {
currentBubbles.remove();
}
}
window.oh = this;
for (var i = 0; i <= 10; i++) {
var timer = Math.random() * 1000;
setTimeout(function() {
window.uh = self;
self.append(bubble);
console.log("oh");
}, 1000);
}
this.randomize = function() {
//self.removeBubbles();
var allBubbles = this.find('.randomBubble');
allBubbles.each(function(i, el) {
var height = Math.random() * settings.maxBubbleSize;
var width = height;
$(el).css({
color: settings.color,
backgroundColor: settings.backgroundColor,
zIndex: 1000,
position: 'absolute',
borderRadius: '50%',
top: self.getTop(height),
left: self.getLeft(width),
height: height,
width: width
});
});
}
this.randomize();
//var run = setInterval(self.randomize, 4000);
return this.find('.randomBubble');
}
})(jQuery);

Because the bubbles are appended later due to the setTimeout(), this selector in your randomize() function comes up empty:
var allBubbles = this.find('.randomBubble');
That is why appending them in a simple for loop works fine.
If you really want to use the setTimout() to append your bubbles, one option is to style them when you add them:
setTimeout(function() {
var height = Math.random() * settings.maxBubbleSize;
var width = height;
var b = $(bubble).css({
color: settings.color,
backgroundColor: settings.backgroundColor,
zIndex: 1000,
position: 'absolute',
borderRadius: '50%',
top: self.getTop(height),
left: self.getLeft(width) ,
height: height,
width: width
});
self.append(b);
}, 1000);
Fiddle

Is it because you still call randomize() right away, even when you postpone the creation for one second?
You will also return an empty selection in that case, for the same reason.
Also, you probably want to use the timer variable in setTimeout() instead of hardcoding all to 1000 ms?

this is a javascript selection, the selector in jquery is $(this)
$.fn.randomBubble = function(options) {
var self = $(this);
};

Overlapping range inputs. On click change input with closest value

I have two overlapping range inputs, this creates a multi range input effect.
I want it so that whenever a click is made on either of these, the input with the closest value to the newly clicked value, is changed. Not entirely sure how to go about this.
How could I do this?
(function() {
"use strict";
var supportsMultiple = self.HTMLInputElement && "valueLow" in HTMLInputElement.prototype;
var descriptor = Object.getOwnPropertyDescriptor(HTMLInputElement.prototype, "value");
self.multirange = function(input) {
if (supportsMultiple || input.classList.contains("multirange")) {
return;
}
var values = input.getAttribute("value").split(",");
var max = +input.max || 100;
var ghost = input.cloneNode();
input.classList.add("multirange", "original");
ghost.classList.add("multirange", "ghost");
input.value = values[0] || max / 2;
ghost.value = values[1] || max / 2;
input.parentNode.insertBefore(ghost, input.nextSibling);
Object.defineProperty(input, "originalValue", descriptor.get ? descriptor : {
// Dang you Safari >:(
get: function() {
return this.value;
},
set: function(v) {
this.value = v;
}
});
Object.defineProperties(input, {
valueLow: {
get: function() {
return Math.min(this.originalValue, ghost.value);
},
set: function(v) {
this.originalValue = v;
},
enumerable: true
},
valueHigh: {
get: function() {
return Math.max(this.originalValue, ghost.value);
},
set: function(v) {
ghost.value = v;
},
enumerable: true
}
});
if (descriptor.get) {
// Again, fuck you Safari
Object.defineProperty(input, "value", {
get: function() {
return this.valueLow + "," + this.valueHigh;
},
set: function(v) {
var values = v.split(",");
this.valueLow = values[0];
this.valueHigh = values[1];
},
enumerable: true
});
}
function update() {
ghost.style.setProperty("--low", input.valueLow * 100 / max + 1 + "%");
ghost.style.setProperty("--high", input.valueHigh * 100 / max - 1 + "%");
}
input.addEventListener("input", update);
ghost.addEventListener("input", update);
update();
}
multirange.init = function() {
Array.from(document.querySelectorAll("input[type=range][multiple]:not(.multirange)")).forEach(multirange);
}
if (document.readyState == "loading") {
document.addEventListener("DOMContentLoaded", multirange.init);
} else {
multirange.init();
}
})();
#supports (--css: variables) {
input[type="range"].multirange {
-webkit-appearance: none;
padding: 0;
margin: 0;
display: inline-block;
vertical-align: top;
width: 250px;
margin-top: 50px;
margin-left: 50px;
background: lightblue;
}
input[type="range"].multirange.original {
position: absolute;
}
input[type="range"].multirange.original::-webkit-slider-thumb {
position: relative;
z-index: 2;
}
input[type="range"].multirange.original::-moz-range-thumb {
transform: scale(1);
/* FF doesn't apply position it seems */
G z-index: 1;
}
input[type="range"].multirange::-moz-range-track {
border-color: transparent;
/* needed to switch FF to "styleable" control */
}
input[type="range"].multirange.ghost {
position: relative;
background: var(--track-background);
--track-background: linear-gradient(to right, transparent var(--low), var(--range-color) 0, var(--range-color) var(--high), transparent 0) no-repeat 0 45% / 100% 40%;
--range-color: hsl(190, 80%, 40%);
}
input[type="range"].multirange.ghost::-webkit-slider-runnable-track {
background: var(--track-background);
}
input[type="range"].multirange.ghost::-moz-range-track {
background: var(--track-background);
}
}
<input type="range" multiple value="10,80" />

You'll have to capture a mouse event on the element and calculate how close it is to the high marker vs. the low marker and decide which one to update based on that. Also, because these are two stacked input elements, you'll probably have to pass the event to the low range input manually.
Here's my go at creating such a function:
function passClick(evt) {
// Are the ghost and input elements inverted? (ghost is lower range)
var isInverted = input.valueLow == ghost.value;
// Find the horizontal position that was clicked (as a percentage of the element's width)
var clickPoint = evt.offsetX / this.offsetWidth;
// Map the percentage to a value in the range (note, assumes a min value of 0)
var clickValue = max * clickPoint;
// Get the distance to both high and low values in the range
var highDiff = Math.abs(input.valueHigh - clickValue);
var lowDiff = Math.abs(input.valueLow - clickValue);
if (lowDiff < highDiff && !isInverted || (isInverted && lowDiff > highDiff)) {
// The low value is closer to the click point than the high value
// We should update the low value input
var passEvent = new MouseEvent("mousedown", {screenX: evt.screenX, clientX: evt.clientX});
// Pass a new event to the low "input" element (which is obscured by the
// higher "ghost" element, and doesn't get mouse events outside the drag handle
input.dispatchEvent(passEvent);
// The higher "ghost" element should not respond to this event
evt.preventDefault();
return false;
}
else {
console.log("move ghost");
// The high value is closer to the click point than the low value
// The default behavior is appropriate, so do nuthin
}
}
ghost.addEventListener("mousedown", passClick);
I put this code immediately above the input.addEventListener("input", update); line in your sample, and it seems to work. See my fiddle.
Some provisos though:
I only tested in Chrome. IE might have some trouble based on how I replicated the event. It may use a mechanism other than dispatchEvent... like fireEvent or something.
Initially I coded it assuming that the "ghost" element always kept track of the high range. I've since updated things to invert the event dispatching when the ghost element has the lower value--but I sped through it.

Here's something simple you could use. Although you might want to customize the style.
I am altering the z-index of the slider element based upon its proximity to the cursor.
JSFiddle
HTML
<input id='a' type='range' />
<input id='b' type='range' />
<label role='info'></label>
JS
var a = document.getElementById('a');
var b = document.getElementById('b');
a.onmousemove = function(e) {
MouseMove.call(a, e);
};
b.onmousemove = function(e) {
MouseMove.call(b, e);
};
var MouseMove = function(eventArg)
{
var max = parseInt(a.max),
min = parseInt(a.min),
diff = max - min,
clickPoint = eventArg.offsetX / a.offsetWidth,
clickPointVal = parseInt(diff * clickPoint) + min;
/* absolute distance from respective slider values */
var da = Math.abs(a.value - clickPointVal),
db = Math.abs(b.value - clickPointVal);
// Making the two sliders appear above one another only when no mouse button is pressed, this condition may be removed at will
if (!eventArg.buttons)
{
if (da < db)
{
a.style.zIndex = 2;
b.style.zIndex = 1;
}
else if (db < da)
{
b.style.zIndex = 2;
a.style.zIndex = 1;
}
}
document.querySelector('label').innerHTML = 'Red: ' + a.value + ', Green: ' + b.value + ', X: ' + eventArg.clientX;
}
CSS
input {
margin: 0px;
position: absolute;
left: 0px;
}
label {
display: inline-block;
margin-top: 100px;
}
#a {
z-index: 2;
}
#b {
z-index: 1;
}

JS .animate() not working in Firefox/IE

So I'm trying to animate a div but I'm not sure what I'm doing wrong here. The following code works just fine on the latest Safari and Chrome but not on Internet Explorer and Firefox.
On Firefox, the error being el.animate is not a function
Any suggestions/solutions?
var slowMo = false;
var dur = slowMo ? 5000 : 500;
function $(id) {
return document.getElementById(id);
}
var players = {};
var hue = 0;
function addTouch(e) {
var el = document.createElement('div');
el.classList.add('ripple');
var color = 'hsl(' + (hue += 70) + ',100%,50%)';
el.style.background = color;
var trans = 'translate(' + e.pageX + 'px,' + e.pageY + 'px) '
console.log(trans);
var player = el.animate([{
opacity: 0.5,
transform: trans + "scale(0) "
}, {
opacity: 1.0,
transform: trans + "scale(2) "
}], {
duration: dur
});
player.playbackRate = 0.1;
players[e.identifier || 'mouse'] = player;
document.body.appendChild(el);
player.onfinish = function() {
if (!document.querySelector('.ripple ~ .pad')) each(document.getElementsByClassName('pad'), function(e) {
e.remove();
});
el.classList.remove('ripple');
el.classList.add('pad');
}
}
function dropTouch(e) {
players[e.identifier || 'mouse'].playbackRate = 1;
}
function each(l, fn) {
for (var i = 0; i < l.length; i++) {
fn(l[i]);
}
}
document.body.onmousedown = addTouch;
document.body.onmouseup = dropTouch;
document.body.ontouchstart = function(e) {
e.preventDefault();
each(e.changedTouches, addTouch);
};
document.body.ontouchend = function(e) {
e.preventDefault();
each(e.changedTouches, dropTouch);
};
var el = document.body;
function prevent(e) {
e.preventDefault();
}
el.addEventListener("touchstart", prevent, false);
el.addEventListener("touchend", prevent, false);
el.addEventListener("touchcancel", prevent, false);
el.addEventListener("touchleave", prevent, false);
el.addEventListener("touchmove", prevent, false);
function fakeTouch() {
var touch = {
pageX: Math.random() * innerWidth,
pageY: Math.random() * innerHeight,
identifier: 'fake_' + Math.random() + '__fake'
}
addTouch(touch);
var length = Math.random() * 1000 + 500;
setTimeout(function() {
dropTouch(touch);
}, length)
setTimeout(function() {
fakeTouch();
}, length - 100)
}
if (location.pathname.match(/fullcpgrid/i)) fakeTouch(); //demo in grid
.ripple {
position: absolute;
width: 100vmax;
height: 100vmax;
top: -50vmax;
left: -50vmax;
border-radius: 50%;
}
body {
overflow: hidden;
}
.pad {
position: absolute;
left: 0;
right: 0;
top: 0;
bottom: 0;
}
<div class="pad"></div>
Code thanks to Kyle

So I took a different approach to achieve the same result. I think this one is a lot more straightforward and works in all browsers.
https://jsfiddle.net/cbrmuxcq/1/
Though there is a slight issue and I'm not sure what causes it. If I don't wait (by using setTimeout()), the transition doesn't happen but by setting a timeout it does. If anyone can spot the issue, I'll fix the fiddle and update my answer accordingly.

How much of an element is visible in viewport

There's a div (brown rectangle) on the page. The page is higher than the viewport (orange rectangle) so it can be scrolled, which means that the div might only partially show up or not at all.
What's the simplest algorithm to tell how much % of the div is visible in the viewport?
(To make things easier, the div always fits into the viewport horizontally, so only the Y axis needs to be considered at the calculations.)

See one more example in fiddle:
https://jsfiddle.net/1hfxom6h/3/
/*jslint browser: true*/
/*global jQuery, window, document*/
(function ($) {
'use strict';
var results = {};
function display() {
var resultString = '';
$.each(results, function (key) {
resultString += '(' + key + ': ' + Math.round(results[key]) + '%)';
});
$('p').text(resultString);
}
function calculateVisibilityForDiv(div$) {
var windowHeight = $(window).height(),
docScroll = $(document).scrollTop(),
divPosition = div$.offset().top,
divHeight = div$.height(),
hiddenBefore = docScroll - divPosition,
hiddenAfter = (divPosition + divHeight) - (docScroll + windowHeight);
if ((docScroll > divPosition + divHeight) || (divPosition > docScroll + windowHeight)) {
return 0;
} else {
var result = 100;
if (hiddenBefore > 0) {
result -= (hiddenBefore * 100) / divHeight;
}
if (hiddenAfter > 0) {
result -= (hiddenAfter * 100) / divHeight;
}
return result;
}
}
function calculateAndDisplayForAllDivs() {
$('div').each(function () {
var div$ = $(this);
results[div$.attr('id')] = calculateVisibilityForDiv(div$);
});
display();
}
$(document).scroll(function () {
calculateAndDisplayForAllDivs();
});
$(document).ready(function () {
calculateAndDisplayForAllDivs();
});
}(jQuery));
div {
height:200px;
width:300px;
border-width:1px;
border-style:solid;
}
p {
position: fixed;
left:320px;
top:4px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="div1">div1</div>
<div id="div2">div2</div>
<div id="div3">div3</div>
<div id="div4">div4</div>
<p id="result"></p>

Here's a snippet illustrating how you can calculate this.
I've put the % values in the boxes for readability, and it even kinda "follows" the viewport ^^ :
Fiddle version
function listVisibleBoxes() {
var results = [];
$("section").each(function () {
var screenTop = document.documentElement.scrollTop;
var screenBottom = document.documentElement.scrollTop + $(window).height();
var boxTop = $(this).offset().top;
var boxHeight = $(this).height();
var boxBottom = boxTop + boxHeight;
if(boxTop > screenTop) {
if(boxBottom < screenBottom) {
//full box
results.push(this.id + "-100%");
$(this).html("100%").css({ "line-height": "50vh" });
} else if(boxTop < screenBottom) {
//partial (bottom)
var percent = Math.round((screenBottom - boxTop) / boxHeight * 100) + "%";
var lineHeight = Math.round((screenBottom - boxTop) / boxHeight * 50) + "vh";
results.push(this.id + "-" + percent);
$(this).html(percent).css({ "line-height": lineHeight });
}
} else if(boxBottom > screenTop) {
//partial (top)
var percent = Math.round((boxBottom - screenTop) / boxHeight * 100) + "%";
var lineHeight = 100 - Math.round((boxBottom - screenTop) / boxHeight * 50) + "vh";
results.push(this.id + "-" + percent);
$(this).html(percent).css({ "line-height": lineHeight });
}
});
$("#data").html(results.join(" | "));
}
$(function () {
listVisibleBoxes();
$(window).on("scroll", function() {
listVisibleBoxes();
});
});
body {
background-color: rgba(255, 191, 127, 1);
font-family: Arial, sans-serif;
}
section {
background-color: rgba(175, 153, 131, 1);
height: 50vh;
font-size: 5vh;
line-height: 50vh;
margin: 10vh auto;
overflow: hidden;
text-align: center;
width: 50vw;
}
#data {
background-color: rgba(255, 255, 255, .5);
left: 0;
padding: .5em;
position: fixed;
top: 0;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<section id="one"></section>
<section id="two"></section>
<section id="three"></section>
<section id="four"></section>
<section id="five"></section>
<section id="six"></section>
<div id="data">data here</div>

After playing around a bit I think I've found perhaps the simplest way to do it: I basically determine how much the element extends over the viewport (doesn't matter in which direction) and based on this it can easily be calculated how much of it is visible.
// When the page is completely loaded.
$(document).ready(function() {
// Returns in percentages how much can be seen vertically
// of an element in the current viewport.
$.fn.pvisible = function() {
var eTop = this.offset().top;
var eBottom = eTop + this.height();
var wTop = $(window).scrollTop();
var wBottom = wTop + $(window).height();
var totalH = Math.max(eBottom, wBottom) - Math.min(eTop, wTop);
var wComp = totalH - $(window).height();
var eIn = this.height() - wComp;
return (eIn <= 0 ? 0 : eIn / this.height() * 100);
}
// If the page is scrolled.
$(window).scroll(function() {
// Setting the opacity of the divs.
$("div").each(function() {
$(this).css("opacity", Math.round($(this).pvisible()) / 100);
});
});
});
html,
body {
width: 100%;
height: 100%;
}
body {
background-color: rgba(255, 191, 127, 1);
}
div {
width: 60%;
height: 30%;
margin: 5% auto;
background-color: rgba(175, 153, 131, 1);
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
A little illustration to help understand how it works:

Chrome now supports Intersection Observer API
Example (TypeScript):
export const elementVisibleInPercent = (element: HTMLElement) => {
return new Promise((resolve, reject) => {
const observer = new IntersectionObserver((entries: IntersectionObserverEntry[]) => {
entries.forEach((entry: IntersectionObserverEntry) => {
resolve(Math.floor(entry.intersectionRatio * 100));
clearTimeout(timeout);
observer.disconnect();
});
});
observer.observe(element);
// Probably not needed, but in case something goes wrong.
const timeout = setTimeout(() => {
reject();
}, 500);
});
};
const example = document.getElementById('example');
const percentageVisible = elementVisibleInPercent(example);
Example (JavaScript):
export const elementVisibleInPercent = (element) => {
return new Promise((resolve, reject) => {
const observer = new IntersectionObserver(entries => {
entries.forEach(entry => {
resolve(Math.floor(entry.intersectionRatio * 100));
clearTimeout(timeout);
observer.disconnect();
});
});
observer.observe(element);
// Probably not needed, but in case something goes wrong.
const timeout = setTimeout(() => {
reject();
}, 500);
});
};
const example = document.getElementById('example');
const percentageVisible = elementVisibleInPercent(example);

Please note that the Intersection Observer API is available since then, made specifically for this purpose.

Issue when sliding element in jquery?

I am trying to develop the following carousel.
http://jsfiddle.net/2kLanjwn/2/
It should work in this way.
Clicking the button DOWN, carousel scrolls and resize always div in the center.
I am not able to apply the same logic on the reverse, so when I click button UP I need to contract the central div, and sliding up.
I kindly you what I am doing wrong and if you would be able to fix it on jsfiddle.
Also I would like to know if there is any better way to achieve that same effect or a component that can be reused.
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Scroll text box example</title>
<style>
#btn-up, #btn-down {
position: absolute;
top: 600px;
}
#btn-up {
left: 0px;
}
#btn-down {
left: 50px;
}
#btn-up, #btn-down {
width: 50px;
height: 50px;
background-color: yellow;
outline: 1px solid black;
}
#content-scroll-container {
position: absolute;
top: 0;
left: 0px;
width: 500px;
height: 250px; /* MASK HEIGHT real mask would be 200*/
overflow: hidden;
}
#content-scroll-inner {
position: absolute;
}
.cnt {
height: 100px;
width: 500px;
background-color: red;
}
.cnt:nth-child(even) {
height: 100px;
background-color: pink;
}
</style>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script>
var scroller = {
config: {
curPos: 0, // position
canExpand: false,
el: 'content-scroll-container', // visible area (container)
elInner: 'content-scroll-inner', // inner content
cntPosY: null, // content top-left corner (0 position)
cntHeight: null, // content lenght
maskHeight: null, // visible area (rest is masked out)
canMoveUp: null, // true jquery can slide up content
canMoveDown: null, // true jquery can slide down content
increment: 100, // slide of x pixel when user perfom an action
incrementOf: 0, // how much we have slided the contnt
animationSpeed: 500, // jquery animation speed, use 0 for no animation
isAnimationOn: false, // true when jquery is performing animation
},
data: '<div id="cnt-0" class="cnt">0</div><div id="cnt-1" class="cnt">1</div><div id="cnt-2" class="cnt">2</div><div id="cnt-3" class="cnt">3</div><div id="cnt-4" class="cnt">4</div><div id="cnt-5" class="cnt">5 empty</div>',
getCntPosition: function () {
// get y position of content
var elm = document.getElementById(this.config.elInner);
this.config.cntPosY = elm.offsetTop;
},
getCntSize: function () {
// get height for content
var elm = document.getElementById(this.config.elInner);
this.config.cntHeight = elm.clientHeight;
},
getMaskSize: function () {
// get height visible area
var elm = document.getElementById(this.config.el);
this.config.maskHeight = elm.clientHeight;
},
updateData: function () {
// refresh state
this.getMaskSize();
this.getCntPosition();
this.getCntSize();
this.canMoveUpCheck();
this.canMoveDownCheck();
//console.clear();
console.log(this.config);
},
canMoveUpCheck: function () {
// set flags allowing sliding up (in case we have enought content to show)
var lastScreenY = (this.config.cntHeight - this.config.maskHeight); // last screen visible
if ((this.config.incrementOf * -1) < lastScreenY)
this.config.canMoveUp = true;
else
this.config.canMoveUp = false;
},
canMoveDownCheck: function () {
// set flags allowing sliding down (in case we have enought content to show)
if (this.config.cntPosY >= 0)
this.config.canMoveDown = false; // cannot move more up if content is on start position (0 position)
else
this.config.canMoveDown = true;
},
goUp: function () {
// user want to read previose content
//this.updateData();
if (this.config.canMoveDown == true && this.config.isAnimationOn == false) {
this.moveCnt('down'); // content go down
}
},
goDown: function () { //**************************
// user want to read next content
//this.updateData();
if (this.config.canMoveUp == true && this.config.isAnimationOn == false) {
// check newPos
var newPos = this.config.curPos + 1;
if (newPos > 0) { // special case
if (this.config.canExpand == true)
this.config.increment = 150;
this.config.canExpand = true;
this.moveCnt('up');
}
}
},
moveCnt: function (direction) {
// do the actual animation
var moveOf;
this.isAnimationOn = true;
if (direction == 'up') {
this.config.curPos++;
if (this.config.cntPosY == 0) { // special case for first item
moveOf = '-=' + (this.config.increment / 2);
}
else {
moveOf = '-=' + this.config.increment;
}
var target = '#' + this.config.elInner + ':not(:animated)';
$(target).animate({ 'top': moveOf }, this.animationSpeed, this.cbEndAnimation.bind(this, direction));
} else if (direction == 'down') {
this.config.curPos++;
var distanceToFp = (this.config.increment / 2); // height to reach first page (special page)
var distanceToFp = 50;
if (this.config.cntPosY == (distanceToFp * -1)) {
moveOf = '+=' + distanceToFp;
// i need to contract only the firs tone
$('cnt-1').css({ height: '100px' }, 500, this.cbEndAnimationExpand.bind(this));
} else {
moveOf = '+=' + this.config.increment;
}
var target = '#' + this.config.elInner + ':not(:animated)';
$(target).animate({ 'top': moveOf }, this.animationSpeed, this.cbEndAnimation.bind(this));
}
//var target = '#' + this.config.elInner + ':not(:animated)';
//$(target).animate({ 'top': moveOf }, this.animationSpeed, this.cbEndAnimation.bind(this, direction));
},
cbEndAnimation: function (direction) {
// runs when animation end
this.config.isAnimationOn = false;
if (direction == 'up') {
this.config.incrementOf -= this.config.increment;
if (this.config.canExpand == true) { // expand
this.logicExpand();
} else {
// do nothing
}
}
else if (direction == 'down') {
this.config.incrementOf += this.config.increment;
}
this.updateData(); // refresh state has element has just moved
this.logicShowHideArrows();
},
logicExpand: function () {
// take contenf and expand it
var elm = document.getElementById('cnt-' + this.config.curPos);
$(elm).animate({ height: '150px' }, 500, this.cbEndAnimationExpand.bind(this));
},
cbEndAnimationExpand: function () {
console.log('end anim expand');
},
logicContract: function () {
var elm = document.getElementById('cnt-' + this.config.curPos);
$(elm).animate({ height: '-=50px' }, 500, this.cbEndAnimationContract.bind(this));
},
logicShowHideArrows: function () {
// reset first
this.hideArrow('btn-up');
this.hideArrow('btn-down');
if (this.config.canMoveUp == true)
this.showArrow('btn-down');
if (this.config.canMoveDown == true)
this.showArrow('btn-up');
},
cbEndAnimationContract: function () {
this.config.isAnimationOn = false;
this.moveCnt('down'); // content go down
},
showArrow: function (elmName) {
var elm = document.getElementById(elmName);
elm.style.display = '';
},
hideArrow: function (elmName) {
var elm = document.getElementById(elmName);
elm.style.display = 'none';
},
setEventHandler: function () {
// envet handlers for arrows
var btnUp = document.getElementById('btn-up');
btnUp.addEventListener('click', this.goUp.bind(this), false);
var btnDown = document.getElementById('btn-down');
btnDown.addEventListener('click', this.goDown.bind(this), false);
},
renderData: function () {
// render data content to slide
var elm = document.getElementById(this.config.elInner);
elm.innerHTML = this.data;
},
start: function () {
this.renderData();
this.updateData();
this.setEventHandler();
this.logicShowHideArrows(); // at start set arrows visibility
}
};
</script>
</head>
<body onload="scroller.start();">
<div id="content-scroll-container">
<div id="content-scroll-inner">
</div>
</div>
<div id="btn-up">UP</div>
<div id="btn-down">DOWN</div>
</body>
</html>

I can't find what in your code is wrong, but I made some changes to it, and it worked. Here is the code
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Scroll text box example</title>
<style>
#btn-up, #btn-down {
position: absolute;
top: 400px;
}
#btn-up {
left: 0px;
}
#btn-down {
left: 50px;
}
#btn-up, #btn-down {
width: 50px;
height: 50px;
background-color: yellow;
outline: 1px solid black;
}
#content-scroll-container {
position: absolute;
top: 0;
left: 0px;
width: 500px;
height: 250px; /* MASK HEIGHT real mask would be 200*/
overflow: hidden;
}
#content-scroll-inner {
position: absolute;
}
.cnt {
height: 100px;
width: 500px;
background-color: red;
}
.cnt:nth-child(even) {
height: 100px;
background-color: pink;
}
</style>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script>
var scroller = {
config: {
curPos: 0, // position
el: 'content-scroll-container', // visible area (container)
elInner: 'content-scroll-inner', // inner content
cntPosY: null, // content top-left corner (0 position)
cntHeight: null, // content lenght
maskHeight: null, // visible area (rest is masked out)
animationSpeed: 500, // jquery animation speed, use 0 for no animation
isAnimationOn: false, // true when jquery is performing animation
},
data: '<div id="cnt-0" class="cnt">0</div><div id="cnt-1" class="cnt">1</div><div id="cnt-2" class="cnt">2</div><div id="cnt-3" class="cnt">3</div><div id="cnt-4" class="cnt">4</div><div id="cnt-5" class="cnt">5 empty</div>',
getCntPosition: function () {
// get y position of content
var elm = document.getElementById(this.config.elInner);
this.config.cntPosY = elm.offsetTop;
},
getCntSize: function () {
// get height for content
var elm = document.getElementById(this.config.elInner);
this.config.cntHeight = elm.clientHeight;
},
getMaskSize: function () {
// get height visible area
var elm = document.getElementById(this.config.el);
this.config.maskHeight = elm.clientHeight;
},
updateData: function () {
// refresh state
this.getMaskSize();
this.getCntPosition();
this.getCntSize();
//console.clear();
console.log(this.config);
},
logicShowHideArrows: function () {
if(this.config.curPos<1) {
$('#btn-up').hide();
} else {
$('#btn-up').show();
}
if(this.config.curPos>=4) {
$('#btn-down').hide();
} else {
$('#btn-down').show();
}
},
goUp: function () {
if(this.config.curPos<4 && scroller.config.isAnimationOn ==false) {
scroller.config.isAnimationOn = true;
scroller.config.curPos++;
if(scroller.config.curPos==1) {
$('#content-scroll-inner').animate({'top':'-=50px'},500,function(){
$('#cnt-'+scroller.config.curPos).animate({'height':'+=50px'},500);
scroller.logicShowHideArrows();
scroller.config.isAnimationOn = false;
});
this.config.incrementOf-=50;
$('#btn-up').show();
}
else {
$('#content-scroll-inner').animate({'top':'-=150px'},500,function(){
$('#cnt-'+scroller.config.curPos).animate({'height':'+=50px'},500);
scroller.logicShowHideArrows();
scroller.config.isAnimationOn = false;
});
this.config.incrementOf-=150;
}
this.updateData();
}
},
goDown: function () { //**************************
// user want to read next content
//this.updateData();
if(this.config.curPos>0 && scroller.config.isAnimationOn ==false) {
scroller.config.isAnimationOn = true;
if(this.config.curPos==1) {
$('#cnt-'+scroller.config.curPos).animate({'height':'-=50px'},500,function(){
$('#content-scroll-inner').animate({'top':'+=50px'},500);
scroller.logicShowHideArrows();
scroller.config.isAnimationOn = false;
});
scroller.config.curPos--;
this.config.incrementOf+=150;
this.updateData();
}
else {
$('#cnt-'+scroller.config.curPos).animate({'height':'-=50px'},500,function(){
$('#content-scroll-inner').animate({'top':'+=150px'},500);
scroller.logicShowHideArrows();
scroller.config.isAnimationOn = false;
});
scroller.config.curPos--;
this.config.incrementOf+=150;
this.updateData();
}
}
},
setEventHandler: function () {
$('#btn-up').click(function() {
scroller.goDown();
});
$('#btn-down').click(function() {
scroller.goUp();
});
},
renderData: function () {
// render data content to slide
var elm = document.getElementById(this.config.elInner);
elm.innerHTML = this.data;
},
start: function () {
this.renderData();
this.updateData();
this.setEventHandler();
this.logicShowHideArrows();
}
};
</script>
</head>
<body onload="scroller.start();">
<div id="content-scroll-container">
<div id="content-scroll-inner">
</div>
</div>
<div id="btn-up">UP</div>
<div id="btn-down">DOWN</div>
</body>
</html>