Develop Reference

Detecting the end of a overflow-x:scroll element and add a class before animation

As the title suggests I want to detect the start and end of a scrollable element built using overflow.
The following code works:
var scrollAmount = 150;
var scrollBox = $('.js-compare_scroll');
var arrowLeft = $('.js-compare_scroll_left');
var arrowRight = $('.js-compare_scroll_right');
var inactive = 'm-inactive';
$(arrowLeft).on('click', function () {
$(this).parent().find(scrollBox).stop().animate({
scrollLeft: '-='+scrollAmount
}, function() {
arrowRight.removeClass(inactive);
if(scrollBox.scrollLeft() === 0) {
arrowLeft.addClass(inactive);
}
});
});
$(arrowRight).on('click', function () {
$(this).parent().find(scrollBox).stop().animate({
scrollLeft: '+='+scrollAmount
}, function() {
arrowLeft.removeClass(inactive);
if(scrollBox.scrollLeft() + scrollBox.innerWidth() >= scrollBox[0].scrollWidth) {
arrowRight.addClass(inactive);
}
});
});
However the class to style the inactive colour of the arrows only appears once the animation completes. I need to add the class before the animation completes because it has a delay. I believe by default it is 400.
Is there anyway to detect this and apply the arrow classes where needed?
Thanks.

Came back from a break and realised I should take the checking if its at the end off the click event and onto a scroll event. This works a lot better now.

Wow.js repeat animation every time you scroll up or down

I'm pretty new with Jquery. I would like that my animations with Wow.js could run more than once time. For instance: i scroll to the bottom of my page and see all the animations, and if i scroll back to the top i see again the animations like when you scroll down. I hope that I explained myself. I have already seen many websites that repeats the animations on theirs pages but unfortunately I don't remember them and I can't provide a link.
I have already tried this:
$(window).scroll(function(){
new WOW().init();
}
But it repeat the animations also if you scroll a little and it's pretty ugly to see. I try to explain me better: I have a with my animation and if it is focused the animation is triggered, then i scroll down to another div and the previous div is no more visible(not in the window viewport), then again i scroll back to my div with animation and the animation is triggered again.
I'm sorry for this messy question but I really don't know how to explain it.
Thanks in advance!

This example by Benoît Boucart shows how the animation can be "reset" when the user scrolls out of view and back in. The key here is the second function that removes the animation css class when the element scrolls out of view. I wish WOW.js would implement this, but they've indicated that they don't plan to.
http://codepen.io/benske/pen/yJoqz
Snippet:
// Showed...
$(".revealOnScroll:not(.animated)").each(function () {
var $this = $(this),
offsetTop = $this.offset().top;
if (scrolled + win_height_padded > offsetTop) {
if ($this.data('timeout')) {
window.setTimeout(function(){
$this.addClass('animated ' + $this.data('animation'));
}, parseInt($this.data('timeout'),10));
} else {
$this.addClass('animated ' + $this.data('animation'));
}
}
});
// Hidden...
$(".revealOnScroll.animated").each(function (index) {
var $this = $(this),
offsetTop = $this.offset().top;
if (scrolled + win_height_padded < offsetTop) {
$(this).removeClass('animated fadeInUp flipInX lightSpeedIn')
}
});

If a user wants to repeat the animation on both the events i.e.
onScrollUp
onScrollDown
then this will be a good solution for it:
First create an addBox function, it will help to push new elements into the WOW boxes array.
WOW.prototype.addBox = function(element){
this.boxes.push(element);
};
Then use jQuery and scrollspy plugin that helps to detect which element is out of the view and then push WOW as:
$('.wow').on('scrollSpy:exit',function(){
var element = $(this);
element.css({
'visibility' : 'hidden',
'animation-name' : 'none'
}).removeClass('animated');
wow.addBox(this);
});
Solution Courtesy: ugurerkan

Answer by #vivekk is correct I m just adding a working example so that people can easily get this
see the Demo fiddle
<script>
// Repeat demo content
var $body = $('body');
var $box = $('.box');
for (var i = 0; i < 20; i++) {
$box.clone().appendTo($body);
}
// Helper function for add element box list in WOW
WOW.prototype.addBox = function(element) {
this.boxes.push(element);
};
// Init WOW.js and get instance
var wow = new WOW();
wow.init();
// Attach scrollSpy to .wow elements for detect view exit events,
// then reset elements and add again for animation
$('.wow').on('scrollSpy:exit', function() {
$(this).css({
'visibility': 'hidden',
'animation-name': 'none'
}).removeClass('animated');
wow.addBox(this);
}).scrollSpy();
</script>

How to get the first entirely visible element within an element that has horizontal scrolling using jQuery?

I need to get the first element that is entirely visible within a scrollable DIV using jQuery. I'm close, but something isn't right.
Can anyone spot the problem?
$('div').on('scroll', function () {
var cutoff = $(this).scrollLeft();
$('li').removeClass('firstVisible').each(function () {
var $this = $(this);
if ($this.offset().left > cutoff) {
$this.addClass('firstVisible');
return false; // stops the iteration after the first one on the screen
}
});
console.log($('li.firstVisible').index());
});
JSFiddle

$this.offset() will return position relative to document (not to div with scrolling), so to check visibility you need to compare it to div position (not scroll left)
$('div').on('scroll', function () {
var cutoff = $(this).offset().left;
$('li').removeClass('firstVisible').each(function () {
var $this = $(this);
if ($this.offset().left >= cutoff) {
$this.addClass('firstVisible');
return false; // stops the iteration after the first one on the screen
}
});
here is an example: http://jsfiddle.net/axwR7/2/

Making nav bar effects using scroll AND click in jQuery

I want a nav to highlight (or something similar) once a user clicks on it AND when a user scrolls to the corresponding section.
However, on my computer when one clicks on any of the nav events after3, only nav event 3 changes. I'm guessing this is because after one clicks on 4 or 5, the scroll bar is already at the bottom of the page, so 4 and 5 never reach the top. The only div at the top is post 3, so my code highlights nav event 3 and ignores the click.
Is there any way I can fix this? Ive tried if statements (only highlight nav event if it's at the top AND the scrollbar isn't at the bottom or the top isn't the last item).
Here is a more accurate fiddle, using a fix below showing what I am talking about. The fix now highlights on scroll, but if you click option 5, it will not highlight.
$('.option').children('a').click(function() {
$('.option').css('background-color', '#CCCCCC;');
$(this).css('background-color', 'red');
var postId = $($(this).attr('href'));
var postLocation = postId.offset().top;
$(window).scrollTop(postLocation);
});
$(window).scroll(function() {
var scrollBar = $(this).scrollTop();
var allPosts = [];
var post = $('.content').offset();
var lastPost = allPosts.legnth-1
var windowHeight = $(window).height();
var bottomScroll = windowHeight-scrollBar;
$(".content").each(function(){
allPosts.push($(this).attr('id'));
});
i = 0;
for(i in allPosts){
var currentPost = "#"+allPosts[i];
var postPosition = $(currentPost).offset().top;
if (scrollBar >= postPosition){
$('.option').css('background-color', '#CCCCCC');
$('#nav'+allPosts[i]).css('background-color', 'red');
};
};
});

I think you've overdone your scroll() handler, to keep it simple you just needs to check if the scrollbar/scrollTop reaches the '.contents' offset top value but should not be greater than its offset().top plus its height().
$(window).scroll(function () {
var scrollBar = $(this).scrollTop();
$(".content").each(function (index) {
var elTop = $(this).offset().top;
var elHeight = $(this).height();
if (scrollBar >= elTop - 5 && scrollBar < elTop + elHeight) {
/* $(this) '.content' is the active on the vewport,
get its index to target the corresponding navigation '.option',
like this - $('.Nav li').eq(index)
*/
}
});
});
And you actually don't need to set $(window).scrollTop(postLocation); because of the default <a> tag anchoring on click, you can omit that one and it will work fine. However if you are looking to animate you need first to prevent this default behavior:
$('.option').children('a').click(function (e) {
e.preventDefault();
var postId = $($(this).attr('href'));
var postLocation = postId.offset().top;
$('html, body').animate({scrollTop:postLocation},'slow');
});
See the demo.

What you are trying to implement from scratch, although commendable, has already been done by the nice folks at Bootstrap. It is called a Scrollspy and all you need to do to implement it is include Bootstrap js and css (you also need jquery but you already have that) and make some minor changes to your html.
Scrollspy implementation steps.
And here is a demonstration. Notice only one line of js. :D
$('body').scrollspy({ target: '.navbar-example' });

Implementing a Parameter to a plugin - Shows 'X' number of elements

The current plugin, shown below, scrolls the top-most div in a series of divs with the same class upwards, then removes it from the container, and appends it to the bottom of the series (within the container). This gives the illusion of a vertical slideshow.
$.fn.rotateEach = function ( opts ) {
var $this = this,
defaults = {
delay: 5000
},
settings = $.extend(defaults, opts),
rotator = function ($elems) {
$elems.eq(0).slideUp(500, function(){
var $eq0 = $elems.eq(0).detach();
$elems.parent().append($eq0);
$eq0.fadeIn();
setTimeout(function(){ rotator( $($elems.selector) ); },
settings.delay);
});
};
setTimeout(function(){ rotator( $this ); }, settings.delay);
};
$('.dynPanelContent').rotateEach();
However, if there are a large number of elements to scroll through, this would make for a VERY long page. As such, I am attempting to re-write this script so that it accepts a parameter which will determine how many elements to display. Any elements exceeding this number will be hidden until they are in the top 'x' number of elements. Here is an example of what I have attempted to implement.
$.fn.rotateEach = function (opts) {
var $this = this,
defaults = {
delay: 5000,
//Add a parameter named elementsShown, pass in a default value of 3
elementsShown: 3
},
settings = $.extend(defaults, opts),
rotator = function ($elems) {
//Hide the elements that are past the number to be shown
for (i = settings.elementsShown; i <= $elems.eq; i++) {
$elems.eq(i).hide();
}
$elems.eq(0).slideUp(500, function () {
var $eq0 = $elems.eq(0).detach();
var $eqN = $elems.eq(settings.elementsShown) - 1;
//Check & Show the element that is now within the show range
if ($elems.eq() == $eqN) {
$elems.eq($eqN).show('slow');
}
$elems.parent().append($eq0);
$eq0.fadeIn();
setTimeout(function () { rotator($($elems.selector)); },
settings.delay);
});
};

You can use simple CSS for this, mate.
If your elements are all of the same height (which your problem has to assume: if you are rotating a whole bunch of things dynamically, you won't want your page to change height), then you don't really need to use JavaScript for this at all. Just set the height of the container to what you want and hide the overflow. Then when you remove and append, everything appears to work. This won't take care of your dynamic configuration, though.

Improved plug-in: http://jsfiddle.net/morrison/tTJaM/
Notes:
Added support for showing X elements.
Added support for rotating only certain elements.
Added support for stopping the rotations:
Stop after X milliseconds.
Stop after X rotations.
overflow-y:hidden is added to container dynamically.
Simplified your detaching/attaching.
Known Issues:
Displaying X elements doesn't check for a maximum.