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' });
Related
I currently have a nav bar within my header that I would like to become fixed after the user scrolls past a certain element. I would also like to achieve the same animation effect as seen at http://pixelmatters.com
When I say 'same' I mean using the same nav bar/header element that I'm using at the top, rather than using a duplicate somewhere else in my document.
I've tried to achieve he result with my own code shown below. I've also included a jsFiddle link of my current setup.
jQuery
var bottomElement = $('.dividerWrap').offset().top + $('.dividerWrap').height();
$(window).on('scoll', function() {
var stop = Math.round($(window).scrollTop());
if (stop > bottomElement) {
$('.header').addClass('isFixed');
} else {
$('.header').removeClass('isFixed');
}
});
https://jsfiddle.net/npfc8wsx/1/
I answered something like that few days ago. please take a look at this code:
$(window).scroll(function () {
var scrollTop = $(window).scrollTop();
var scrollToVid = $('#test').offset().top
console.log(scrollTop); //see window scroll distance //
console.log(scrollToVid); //see scroll to div offest//
if ($(window).scrollTop() >= scrollToVid) {
alert('You reached to the video!');
}
});
jSFiddle
Main Question
now for you some code must change:
$(window).scroll(function () {
var scrollToElem = $('.dividerWrap').offset().top
if ($(window).scrollTop() >= scrollToElem) {
$('.header').addClass('isFixed');
} else {
$('.header').removeClass('isFixed');
}
});
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>
i want to create a menu for a single page website with link to div from page.
The menu look like this:
<li>Home</li>
...
<div id="home-link"></div>
I want to change color of link from menu when i am in area of home-link div. How is possible to make that thing?
Thanks for answers and for your help.
Have a nice day.
You will need JavaScript for this if the link element is not a child of #home-link.
Something like this:
$('#home-link').on('hover', function () {
$('li a').css('color', '#bada55');
});
This assumes you are using jQuery, but similar approach with other frameworks would work as well.
If I assume from the question that if you are hovering on #home-link and color of anchor should change, then
$('#home-link').hover(function () {
$('li a').css('color', 'red');
});
or if I assume that if the id is present in your page and you want to change the color of the anchor then
if($('#home-link').length){
$('li a').css('color', 'red');
}
I found myself with (what I believe is) the same question: how can I change which navigation link is highlighted to reflect the area I've scrolled to, whether I get there by using the link or just by scrolling down the page?
Here's a page with a very helpful tutorial.
The theory:
We create an array of all our nav a href’s. We then use some calculations using the scroll function. We find the section id, calculate it’s height, see if it’s greater or less than the value from the window top, and if the window falls in between, we add a class nav-active to the list item in question. We create a conditional also, because if the top of a section is not reached and the page can’t scroll anymore, we want to highlight this section.
And the relevant jQuery code:
/**
* This part handles the highlighting functionality.
* We use the scroll functionality again, some array creation and
* manipulation, class adding and class removing, and conditional testing
*/
var aChildren = $("nav li").children(); // find the a children of the list items
var aArray = []; // create the empty aArray
for (var i=0; i < aChildren.length; i++) {
var aChild = aChildren[i];
var ahref = $(aChild).attr('href');
aArray.push(ahref);
} // this for loop fills the aArray with attribute href values
$(window).scroll(function(){
var windowPos = $(window).scrollTop(); // get the offset of the window from the top of page
var windowHeight = $(window).height(); // get the height of the window
var docHeight = $(document).height();
for (var i=0; i < aArray.length; i++) {
var theID = aArray[i];
var divPos = $(theID).offset().top; // get the offset of the div from the top of page
var divHeight = $(theID).height(); // get the height of the div in question
if (windowPos >= divPos && windowPos < (divPos + divHeight)) {
$("a[href='" + theID + "']").addClass("nav-active");
} else {
$("a[href='" + theID + "']").removeClass("nav-active");
}
}
if(windowPos + windowHeight == docHeight) {
if (!$("nav li:last-child a").hasClass("nav-active")) {
var navActiveCurrent = $(".nav-active").attr("href");
$("a[href='" + navActiveCurrent + "']").removeClass("nav-active");
$("nav li:last-child a").addClass("nav-active");
}
}
});
I am having this problem where i have a set of 6 UL's having a common class x.Each of them consist of a specific section of the page.Now i have 6 menus that are related to each of the section.What i have to do is highlight the menu when its related section is in users view.
For this i thought that may be jQuery position(); or offset(); could have helped but they give the top and left of the element.I also tried using jQuery viewport plugin but apparently view port is big it can show more than one UL at a time hence i cant apply element specific logic here.I am not familliar to this but does anything changes of an element on scrolling?If yes then how to access it?
Please share your views.
Regards
Himanshu Sharma.
Is very easy to do it using jQuery and a dummy fixed HTML block that helps you find the current position of the viewport.
$(window).on("scroll load",function(){
var once = true;
$(".title").each(function(ele, index){
if($(this).offset().top > $("#viewport_helper").offset().top && once){
var index = $(this).index(".title");
$(".current").removeClass('current')
$("#menu li").eq(index).addClass('current')
once = false;
}
});
})
Check out a working example: http://jsfiddle.net/6c8Az/1/
You could also do something similar with the jQuery plugin, together with the :first selector:
$(window).on("scroll load",function(){
$(".title:in-viewport:first").each(function(){
var index = $(this).index(".title");
$(".current").removeClass('current')
$("#menu li").eq(index).addClass('current')
});
})
You can get the viewport's width and height via $(document).width() and $(document).height()
You can get how many pixels user scrolls via $(document).scrollTop() and $(document).scrollLeft
Combining 1 and 2, you can calculate where the viewport rectangle is
You can get the rectangle of an element using $(element).offset(), $(element).width() and $(element).height()
So the only thing left to you is to determine whether the viewport's rectangle contains (or interacts) the elements's rectangle
So the whole code may look like:
/**
* Check wether outer contains inner
* You can change this logic to matches what you need
*/
function rectContains(outer, inner) {
return outer.top <= inner.top &&
outer.bottom >= inner.bottom &&
outer.left <= inner.left &&
outer.right >= inner.right;
}
/**
* Use this function to find the menu related to <ul> element
*/
function findRelatedMenu(element) {
return $('#menu-' + element.attr('id'));
}
function whenScroll() {
var doc = $(document);
var elem = $(element);
var viewportRect = {
top: doc.scrollTop(),
left: doc.scrollLeft(),
width: doc.width(),
height: doc.height()
};
viewportRect.bottom = viewportRect.top + viewportRect.height;
viewportRect.right = viewportRect.left + viewportRect.width;
var elements = $('ul.your-class');
for (var i = 0; i < elements.length; i++) {
var elem = $(elements[i]);
var elementRect = {
top: elem.offset().top,
left: elem.offset().left,
width: elem.width(),
height: elem.height()
};
elementRect.bottom = elementRect.top + elementRect.height;
elementRect.right = elementRect.left + elementRect.width;
if (rectContains(viewportRect, elementRect)) {
findRelatedMenu(elem).addClass('highlight');
}
}
}
$(window).on('scroll', whenScroll);
Let's see if i understood well. You have a page long enough to scroll, and there is an element that when it appears in the viewport, you wanna do something with it. So the only event that's is triggered for sure on the time the element gets in the viewport is the 'scroll'. So if the element is on the page and the scroll is on the viewport, what you need to do is bind an action to the scroll event to check if the element is in the view each time the event is trigger. Pretty much like this:
$(window).scroll(function() {
check_element_position();
});
Now, in order for you to know if the element is in the viewport, you need 3 things. The offset top of that element, the size of the viewport and the scroll top of the window. Should pretty much look like this:
function check_element_position() {
var win = $(window);
var window_height = win.height();
var element = $(your_element);
var elem_offset_top = element.offset().top;
var elem_height = element.height();
var win_scroll = win.scrollTop();
var pseudo_offset = (elem_offset_top - win_scroll);
if (pseudo_offset < window_height && pseudo_offset >= 0) {
// element in view
}
else {
// elem not in view
}
}
Here, (elem_offset_top - win_scroll) represent the element position if there was no scroll. Like this, you just have to check if the element offset top is higher then the window viewport to see if it's in view or not.
Finally, you could be more precise on you calculations by adding the element height (variable already in there) because the code i just did will fire the event even if the element is visible by only 1 pixels.
Note: I just did that in five minutes so you might have to fix some of this, but this gives you a pretty darn good idea of what's going on ;)
Feel free to comment and ask questions
I have a scrolling div containing list items. I have this boilerplate scroll event defined
$("#scrollingDiv").scroll(function(e) {
});
Inside of this scroll event function, how can I figure out which elements are at the top and bottom of the currently visible area?
You could try computing the positions of the list items with respect to the scrolling <div> and then scan the positions to see which ones match up with the scrollTop of the <div>.
Something like this perhaps:
var base = $('#scrollingDiv').offset().top;
var offs = [ ];
$('li').each(function() {
var $this = $(this);
offs.push({
offset: $this.offset().top - base,
height: $this.height()
});
});
$("#scrollingDiv").scroll(function() {
var y = this.scrollTop;
for(var i = 0; i < offs.length; ++i) {
if(y < offs[i].offset
|| y > offs[i].offset + offs[i].height)
continue;
// Entry i is at the top so do things to it.
return;
}
});
Live version (open your console please): http://jsfiddle.net/ambiguous/yHH7C/
You'd probably want to play with the fuzziness of the if to get something that works sensibly (1px visible hardly makes an element the top one) but the basic idea should be clear enough. Mixing in the height of #scrollingDiv will let you see which <li> is at the bottom.
If you have a lot of list items, then a linear search might not be what you want but you should be able to solve that without too much effort.