Develop Reference

Animate when certain pixels into viewport (Pen by Bramus)

I'm using the following pen by Bramus to animate(FadeInUp) divs when entering the viewport. However currently the div only starts fading in when the div is completely in the viewport. What I need is the flexibility to start the animation when a div is a certain pixels inside the viewport. For example it will start the animation FadeInUp when the div is 100 pixels in the viewport. How can I do this with the current code/pen I'm using (see code below)?
Is this also possible with percentages? F.e. when a div is 20% in viewport the animation starts?
Thanks.
jQuery(function($) {
// Function which adds the 'animated' class to any '.animatable' in view
var doAnimations = function() {
// Calc current offset and get all animatables
var offset = $(window).scrollTop() + $(window).height(),
$animatables = $('.animatable');
// Check all animatables and animate them if necessary
$animatables.each(function(i) {
var $animatable = $(this);
if (($animatable.offset().top + $animatable.height() - 20) < offset) {
$animatable.removeClass('animatable').addClass('animated');
}
});
};
// Hook doAnimations on scroll, and trigger a scroll
$(window).on('scroll', doAnimations);
$(window).trigger('scroll');
});

Offsetting is already foreseen in the code. Tweak the value of 20 in this line:
if (($animatable.offset().top + $animatable.height() - 20) < offset) {
You might also need to change the - sign to a + to suit your needs.

Erratic scrollbar using Jquery

This is the fiddle. https://jsfiddle.net/igor_g/ksjkpg0t/16/
My intention is to build a scrollbar on a strip of colors. The colors are taken from the text it is supposed to scroll. Basically, the strip is an overview of all the colors that are used in the text fonts. The text is generated dynamically and can be very large and very small. My intention is to make the scroller's size proportional and at the same time scroll properly. I have tried various combinations using jquery but I just can not seem to get the scroller to work the way I want. Sometimes, the scroller doesnt seem to point to the right text passage. How can this be fixed?
The jquery code is as follows:
/// here is our plugin declaration
(function ( $ ) {
$.fn.colorScroller = function( options ) {
var settings = $.extend({
replaceBlack: 'rgb(83, 84, 72)',
colorScrollClass: "color-map",
overlayClass: "overlay",
scrollSectionClass: "mapSection",
coloredTextClass: "passage"
}, options );
// assign this(the selector that is calling this function) to container
var container = this;
// getting the height of container
var containerHeight = container.outerHeight(true);
// creating overlay scrolling element
var $overlay = $('<div class="'+settings.overlayClass+'" ></div>')
//creating container for colored parts
var $colorScroll=$('<div class="'+settings.colorScrollClass+'" ></div>')
// appending colormap element after container in DOM
container.after($colorScroll);
// approximate total height of browser vertical scroll buttons
var browserScrollButtons = 26;
// setting height of colorscroll element to the height of container
$colorScroll.outerHeight(container.outerHeight()-browserScrollButtons );
var scrollerHandleMin = 31
// here we are calculating the total height of text elements of container
var totalHeight = 0;
container.children('.'+ settings.coloredTextClass).each(function(){
totalHeight = totalHeight + $(this).outerHeight(true);
});
// calculate height of text empty elements like br or <p></p>
var emptyHeight = 0;
container.children().not('.'+ settings.coloredTextClass).each(function(){
emptyHeight = emptyHeight + $(this).outerHeight(true);
});
// here we are calculating the ratio b/n total height of children of container and the height of color-scroll element
var ratio = totalHeight/$colorScroll.outerHeight();
// here we create a jquery object containing of small divs which will be colored, and associated with each passage div in container
var $mini = $('.'+settings.coloredTextClass, container).map(function(){
// getting the height of passage, setting the height of small div element by dividing by ratio
var heightPassage=$(this).outerHeight(true)/ratio+'px';
// getting the color of passage
var colorPassage=$(this).css('color');
// color change if color is black
if (colorPassage=='rgb(0, 0, 0)')
colorPassage = settings.replaceBlack;
var elem = $('<div class="'+settings.scrollSectionClass+'" style="height:'+heightPassage+'; background-color:'+colorPassage+'" ></div>').get(0)
// returning a jquery object element with class, height and color associated according to previous calculations
return elem
});
// get approximate height of browser scroll bar handle
var browserScrollBarHeight = (containerHeight*(containerHeight-browserScrollButtons ))/(totalHeight + emptyHeight )
browserScrollBarHeight = browserScrollBarHeight > scrollerHandleMin ? browserScrollBarHeight : scrollerHandleMin
// set overlay scroller height to browser scroll handle height
$overlay.outerHeight(browserScrollBarHeight);
var overlayHeight = $overlay.outerHeight();
// appending the minified elements into colorscroll element
$($mini).appendTo($colorScroll);
// appending overlay element into color-scroll element
$colorScroll.append($overlay);
// getting top position of container related to document top
var colorScrollTop = $colorScroll.offset().top+1+parseInt($colorScroll.css('margin-top').replace('px', ''))
// getting multiple to create algorithm for converting top positions
var k = (totalHeight + emptyHeight - containerHeight)/($colorScroll.innerHeight()-overlayHeight)
// attaching draggable to overlay scrolling element, so that it can be moved along color scroll element
$overlay.draggable({
// constrain movement to color-scroll element only
containment: "."+settings.colorScrollClass,
// what to do when overlay is dragged
drag: function() {
// getting top position of overlay related to document top
var top = $(this).offset().top;
container.animate({
// scroll container vertically to the point of overlay top (related to color-scroll element ) associated with text in container
scrollTop: (top-colorScrollTop)*k +'px'
}, 2)
},
});
/// when mouse on color-scroller unbind container scroll and enble draggable
/// when mouse leaves color-scroller bind container scroll and disable draggable
$colorScroll
.mouseenter(function() {
$overlay.draggable('enable')
container.off('scroll', scrollText)
})
.mouseleave(function() {
$overlay.draggable('disable')
container.on('scroll', scrollText)
});
// function triggered when container scrolled, basically scroll the overlay
function scrollText(){
$overlay.animate({
top: container.scrollTop()/k + 'px'
}, 1)
}
container.on('scroll', scrollText)
// when the color-scroll element is clicked
$colorScroll.on('click',function(e){
// calculate the position of click related to color-scroll itself
var topPosition = e.pageY-$(this).offset().top;
// and move overlay top to that position
$overlay.animate({
top: topPosition+'px'
}, 200)
// and scroll container to text associated with overlay top
container.animate({
scrollTop: (topPosition+overlayHeight)*ratio-containerHeight+'px'
}, 10)
})
return container;
};
}( jQuery ));
/// end plugin
$(document).ready(function() {
var passes = [0, 1, 2, 3, 4, 5, 6]
for (var i in passes) {
col = document.getElementById('pass' + i).style.color;
var element = document.createElement("section");
element.style.background = col;
document.getElementById("left").appendChild(element);
}
canvas = document.createElement("canvas");
canvas.id = 'canvas';
canvas.style = 'height:700px;width:50px;';
/// here we init plugin function
$('#document_content').colorScroller({replaceBlack: 'rgb(0,0,0)'});
/// the other option with defaults are :
// colorScrollClass: "color-map", css class of colored scrollbar
// overlayClass: "overlay", css class of the custom scrollbar
// scrollSectionClass: "mapSection", css class of the small colored sections in colored scroll bar
// coloredTextClass: "passage" css class of the original text part
///
});

How to use jQuery scroll to change the height of an element?

I have a HTML class navigation with the initial height of 100px and min-height is 40px. I want to change the height of the class, based on the scroll (if scroll down than size will decrease and if scroll up than size will increase). I use the following code and it's working perfectly.
$(window).scroll( function() {
if( $('.navigation').offset().top > 50 )
{
$('.navigation').css({
'height' : '40px',
'background' : 'rgba(37, 37, 37, 0.9)'
});
} else {
$('.navigation').css({
'height' : '100px',
'background' : '#b24926'
});
}
});
If I press the keyboard down arrow key two times than navigation class moved from original height to minimum height and if the up arrow key press two times than navigation class moved from minimum height to original height.
But I want to make the scroll more smooth (like 4-5 up or down key presses to reach from one height to another).
For example: initial height is: 100px and minimum height is 30px. Now:
if down arrow key is pressed/mouse wheel is move down one time than height will be 85px, if again down arrow is pressed height will be 70px and so on. That means for each down arrow key is pressed/mouse wheel is move down than height will decrease by 15-20px and for each up arrow key is pressed/mouse wheel is move up, height will increase by 15-20px.
Can anyone tell me how can I do that (without using third party api).
Thanks

You can use simple percent calculation to update height
var limitForMinimalHeight = 400; //after this distance navigation will be minimal height
var maxHeight = 100;
var minHeight = 40;
$(window).scroll( function() {
var screenTop = $(document).scrollTop();
var achievedDistancePercent = Math.min(screenTop*100/limitForMinimalHeight, 100);
var amounToAdd = ((maxHeight - minHeight) * (100 - achievedDistancePercent))/100;
var newHeight = minHeight + amounToAdd;
$('.navigation').height(newHeight);
});
You can test it on JSFiddle

$(document).scroll(function() {
if($(this).scrollTop()>100) {
$('.selector').addClass('scrolled');
}
if($(this).scrollTop()<40) {
$('.selector').removeClass('scrolled');
}
});

How to detect if any divs are overlapping/'touching' a specific div?

Background Summary
I have a toggle menu that moves and slides down upon document load. However the web page is responsive. So on bigger screen sizes there is empty room for the menu to unroll but some pages contain IMG, DIV, or SPAN tags that rearrange themselves via media queries and take up the needed space for the menu.
Thus one of two things can happen (that are not desired):
a) The page loads, the menu begins to slide open but there is already one of the aforementioned HTML objects already located in its path so the menu unrolls over it, making things look ugly.
b) A mobile visitor enters the site using landscape view and the menu unrolls with nothing in its path, but then the user changes to portrait view causing (sometimes) an HTML tag to overlap the menu.
Desired Result:
I would like the menu to react to its environment so that if some other DIV encroaches on its space, the menu would automatically trigger the click event on itself which would cause it roll back up and sit on its perch on top of the screen.
This would also mean that as it unrolls initially , the menu should be either 'aware' of what is below it and in the case something is there, to not unroll in the first place; or unroll until it touches some other html object in its way, and immediately reverse course and roll back up to its perch.
One quick look is worth a thousand sentences, so please take a look at jsfiddle below.
JSFiddle Setup of Current Code
http://jsfiddle.net/Nick_Wordpress/jLeGq/1/
Current Working Code
jQuery(window).load(function() {
if (jQuery(".toggle").is(":hidden")) {
jQuery(".toggler").trigger("click");
}
});
jQuery(".toggler").on("click touchstart", function() {
toggler = jQuery(this);
room_navigation_top = 150;
pos = 20;
room_navigation_left = 80;
toggler.next(".toggle").is(":visible") ? toggler.next(".toggle").slideUp(function() {
toggler.addClass("minimized").removeClass("maximized").find(".indicator").text("+");
toggler.parent().animate({top:pos + "px", left:pos + "px"});
}) : ("object" == typeof event.originalEvent && (lock_room_navigation = !0), toggler.parent().animate({top:room_navigation_top + "px", left:room_navigation_left + "px"}, function() {
toggler.addClass("maximized").removeClass("minimized").find(".indicator").text("-");
toggler.next(".toggle").slideDown();
}));
});
Thanks in advance for any input towards solving this issue.

Decide whether to expand the menu or not after you've calculated whether it would overlap any other elements. (Expanding first and then checking if you need to collapse it again would be an ugly solution)
Check for potential overlapping by calculating where the menu would be positioned on expansion, and compare that position to the elements which it could overlap.
You should be able to figure out the expanded size if you know the number of menu items and the size of each menu item. Use the top, bottom, left and right properties together with the height and width to figure out the position.
Compare the calculated position of the positions of the elements that risk being overlapped.
Here's some example code for calculating overlap (not written by me): http://jsfiddle.net/98sAG/
function getPositions( elem ) {
var pos, width, height;
pos = $( elem ).position();
width = $( elem ).width();
height = $( elem ).height();
return [ [ pos.left, pos.left + width ], [ pos.top, pos.top + height ] ];
}
function comparePositions( p1, p2 ) {
var r1, r2;
r1 = p1[0] < p2[0] ? p1 : p2;
r2 = p1[0] < p2[0] ? p2 : p1;
return r1[1] > r2[0] || r1[0] === r2[0];
}

How do I get an element to scroll into view, using jQuery?

I have an HTML document with images in a grid format using <ul><li><img.... The browser window has both vertical & horizontal scrolling.
Question:
When I click on an image <img>, how then do I get the whole document to scroll to a position where the image I just clicked on is top:20px; left:20px ?
I've had a browse on here for similar posts...although I'm quite new to JavaScript, and want to understand how this is achieved for myself.

There's a DOM method called scrollIntoView, which is supported by all major browsers, that will align an element with the top/left of the viewport (or as close as possible).
$("#myImage")[0].scrollIntoView();
On supported browsers, you can provide options:
$("#myImage")[0].scrollIntoView({
behavior: "smooth", // or "auto" or "instant"
block: "start" // or "end"
});
Alternatively, if all the elements have unique IDs, you can just change the hash property of the location object for back/forward button support:
$(document).delegate("img", function (e) {
if (e.target.id)
window.location.hash = e.target.id;
});
After that, just adjust the scrollTop/scrollLeft properties by -20:
document.body.scrollLeft -= 20;
document.body.scrollTop -= 20;

Since you want to know how it works, I'll explain it step-by-step.
First you want to bind a function as the image's click handler:
$('#someImage').click(function () {
// Code to do scrolling happens here
});
That will apply the click handler to an image with id="someImage". If you want to do this to all images, replace '#someImage' with 'img'.
Now for the actual scrolling code:
Get the image offsets (relative to the document):
var offset = $(this).offset(); // Contains .top and .left
Subtract 20 from top and left:
offset.left -= 20;
offset.top -= 20;
Now animate the scroll-top and scroll-left CSS properties of <body> and <html>:
$('html, body').animate({
scrollTop: offset.top,
scrollLeft: offset.left
});

Simplest solution I have seen
var offset = $("#target-element").offset();
$('html, body').animate({
scrollTop: offset.top,
scrollLeft: offset.left
}, 1000);
Tutorial Here

There are methods to scroll element directly into the view, but if you want to scroll to a point relative from an element, you have to do it manually:
Inside the click handler, get the position of the element relative to the document, subtract 20 and use window.scrollTo:
var pos = $(this).offset();
var top = pos.top - 20;
var left = pos.left - 20;
window.scrollTo((left < 0 ? 0 : left), (top < 0 ? 0 : top));

Have a look at the jQuery.scrollTo plugin. Here's a demo.
This plugin has a lot of options that go beyond what native scrollIntoView offers you. For instance, you can set the scrolling to be smooth, and then set a callback for when the scrolling finishes.
You can also have a look at all the JQuery plugins tagged with "scroll".

Here's a quick jQuery plugin to map the built in browser functionality nicely:
$.fn.ensureVisible = function () { $(this).each(function () { $(this)[0].scrollIntoView(); }); };
...
$('.my-elements').ensureVisible();

After trial and error I came up with this function, works with iframe too.
function bringElIntoView(el) {
var elOffset = el.offset();
var $window = $(window);
var windowScrollBottom = $window.scrollTop() + $window.height();
var scrollToPos = -1;
if (elOffset.top < $window.scrollTop()) // element is hidden in the top
scrollToPos = elOffset.top;
else if (elOffset.top + el.height() > windowScrollBottom) // element is hidden in the bottom
scrollToPos = $window.scrollTop() + (elOffset.top + el.height() - windowScrollBottom);
if (scrollToPos !== -1)
$('html, body').animate({ scrollTop: scrollToPos });
}

My UI has a vertical scrolling list of thumbs within a thumbbar
The goal was to make the current thumb right in the center of the thumbbar.
I started from the approved answer, but found that there were a few tweaks to truly center the current thumb. hope this helps someone else.
markup:
<ul id='thumbbar'>
<li id='thumbbar-123'></li>
<li id='thumbbar-124'></li>
<li id='thumbbar-125'></li>
</ul>
jquery:
// scroll the current thumb bar thumb into view
heightbar = $('#thumbbar').height();
heightthumb = $('#thumbbar-' + pageid).height();
offsetbar = $('#thumbbar').scrollTop();
$('#thumbbar').animate({
scrollTop: offsetthumb.top - heightbar / 2 - offsetbar - 20
});

Just a tip. Works on firefox only
Element.scrollIntoView();

Simple 2 steps for scrolling down to end or bottom.
Step1: get the full height of scrollable(conversation) div.
Step2: apply scrollTop on that scrollable(conversation) div using the value
obtained in step1.
var fullHeight = $('#conversation')[0].scrollHeight;
$('#conversation').scrollTop(fullHeight);
Above steps must be applied for every append on the conversation div.

After trying to find a solution that handled every circumstance (options for animating the scroll, padding around the object once it scrolls into view, works even in obscure circumstances such as in an iframe), I finally ended up writing my own solution to this. Since it seems to work when many other solutions failed, I thought I'd share it:
function scrollIntoViewIfNeeded($target, options) {
var options = options ? options : {},
$win = $($target[0].ownerDocument.defaultView), //get the window object of the $target, don't use "window" because the element could possibly be in a different iframe than the one calling the function
$container = options.$container ? options.$container : $win,
padding = options.padding ? options.padding : 20,
elemTop = $target.offset().top,
elemHeight = $target.outerHeight(),
containerTop = $container.scrollTop(),
//Everything past this point is used only to get the container's visible height, which is needed to do this accurately
containerHeight = $container.outerHeight(),
winTop = $win.scrollTop(),
winBot = winTop + $win.height(),
containerVisibleTop = containerTop < winTop ? winTop : containerTop,
containerVisibleBottom = containerTop + containerHeight > winBot ? winBot : containerTop + containerHeight,
containerVisibleHeight = containerVisibleBottom - containerVisibleTop;
if (elemTop < containerTop) {
//scroll up
if (options.instant) {
$container.scrollTop(elemTop - padding);
} else {
$container.animate({scrollTop: elemTop - padding}, options.animationOptions);
}
} else if (elemTop + elemHeight > containerTop + containerVisibleHeight) {
//scroll down
if (options.instant) {
$container.scrollTop(elemTop + elemHeight - containerVisibleHeight + padding);
} else {
$container.animate({scrollTop: elemTop + elemHeight - containerVisibleHeight + padding}, options.animationOptions);
}
}
}
$target is a jQuery object containing the object you wish to scroll into view if needed.
options (optional) can contain the following options passed in an object:
options.$container - a jQuery object pointing to the containing element of $target (in other words, the element in the dom with the scrollbars). Defaults to the window that contains the $target element and is smart enough to select an iframe window. Remember to include the $ in the property name.
options.padding - the padding in pixels to add above or below the object when it is scrolled into view. This way it is not right against the edge of the window. Defaults to 20.
options.instant - if set to true, jQuery animate will not be used and the scroll will instantly pop to the correct location. Defaults to false.
options.animationOptions - any jQuery options you wish to pass to the jQuery animate function (see http://api.jquery.com/animate/). With this, you can change the duration of the animation or have a callback function executed when the scrolling is complete. This only works if options.instant is set to false. If you need to have an instant animation but with a callback, set options.animationOptions.duration = 0 instead of using options.instant = true.