I currently have a sidenavigation bar which continually checks the users scroll position and if it is greater than a specified .slide height, it adds a class .current to a certain div on a sidebar making it turn orange and thus indicates which part of a page the user is on. Right now, the code only works for one specific height of .slide but I would like to modify it so that each slide (i.e. slide red, slide green, slide blue which are the divs with the colored background) can be of different heights since my content for each section will vary in length.
The fiddle can be found here
JavaScript:
$(document).scroll(function() {
if($(window).scrollTop() > $('.slide').height()*$('.current').index()){
$('.current').removeClass('current');
var newSlide = Math.floor($(window).scrollTop() / $('.slide').height());
$('.sidenavigation li:eq('+newSlide+')').addClass('current');
}
if($(window).scrollTop() < $('.slide').height()*$('.current').index()){
$('.current').removeClass('current');
var newSlide = Math.floor($(window).scrollTop() / $('.slide').height());
$('.sidenavigation li:eq('-newSlide-')').addClass('current');
}
});
I was trying to help you with your code and then i realize how hard it is, so I know it is probably not what you really want, but I recommend you a great jQuery plugin, which will solve your problem very fast: http://imakewebthings.com/jquery-waypoints/
Related
I'm working on a new portfolio for myself, using Bootstrap framework and I want to animate my slider based on the direction that the user is scrolling.
For example I already have an animation to slide the navbar class in. But as the user scrolls down the page I want to hide the navbar this is to give the user more visibility on the screen when browsing content. Then when they attempt to scroll back up the page I want to slide the .navbar class back in again.
Now I can easily get this to work if I target a specific element or pixel height, but that doesn't help me. I know it's achievable as I've seen it on several websites (LinkedIn for example).
So I'm wondering if it's a case of targeting positive or negative values on the y axis or something?
var lastScrollPosition = 0;
window.onscroll = function() {
var newScrollPosition = window.scrollY;
if (newScrollPosition < lastScrollPosition){
//upward - code here
}else{
//downward - code here
}
lastScrollPosition = newScrollPosition;
}
I just used this code to get my menu highlighted as I scroll down to each each section of my WordPress site:
(function($) {
$(document).ready(function(){
$("header nav ul").toggleClass("open");
$("section.container").addClass("section");
});
$(window).scroll(function() {
var position = $(this).scrollTop();
$('.section').each(function() {
var target = $(this).offset().top;
var id = $(this).attr('id');
if (position >= target) {
$('#primary-menu > li > a').removeClass('active');
$('#primary-menu > li > a[href=#' + id + ']').addClass('active');
}
});
});
}(jQuery));
css:
.active{
color: #fff !important;
}
Here is the link: http://scentology.burnnotice.co.za
Problem is that the last item(Contact) is not getting highlighted when I scroll all the way down up to contact section.
Also,if I click on a menu item,it goes to the respective section but that menu doesn't get highlighted unless I scroll the page a little bit down'.
How can I solve that?
Thanks in advance
NOTE: It seems that you took that code from my answer to this SO question, I have edited it to cover your case. Other people looking for more code can check it out for a snippet.
So, you have two problems:
The last item is not getting highlighted.
When clicking on a menu item, the page scrolls to the respective section but that menu doesn't get highlighted unless scrolling down the page a little bit.
Problem 1
This one is easy, you just forgot to add the id attribute to the last section :)
It should be:
<section id="contact" class="container contact-us section">
Problem 2
Your click event starts a scroll animation to the corresponding section but, since the navigation bar is on the top of the page, you made the animation to leave a little margin on the top. That margin prevents the section from reaching the top of the page, so the menu item doesn't get highlighted.
#Shnibble pointed you in the right direction, you can add a small positive margin to the value returned by $(window).scrollTop() (or a negative one to the offset().top of the element).
So, following the code you have included, it will be something like:
if (position + my_margin >= target) {
The margin could be the height of your navigation bar:
my_margin = $('#site-navigation').height();
You can, obviously, add a little more or less to tailor it to your needs.
There is a simple solution and it just requires a bit of additional math :)
You are measuring from the top of the (window) viewport and checking to see if it is greater than or equal to the top of a specified target div. Because your content sections are exactly 100% of the viewport, it is impossible for the top of the viewport ever be greater than or equal to the top of the last content div.
What you need to do is offset the point you are measuring from so that you are not measuring from the top of the viewport, but rather some ways down from the top, say halfway or 3/4 of the way down. This will solve both of your issues.
Edit: here is something to get you started, then play around with dividing the window height by 1/2 or something like that:
var position = $(this).scrollTop() + $(window).height;
Let me start of by saying, I'm just now learning JS and Jquery, so my knowledge is very limited.
I've been looking around for 2 days now, and tried all sorts of combinations. But I just can't get this to work.
Below is an example of the layout
I'm looking for a way to trigger an event when div 1 is X px from the top of the screen. Or when div 1 collides with div 2.
What I'm trying to accomplish is to change the css of div 2 (the fixed menu) when div 1 is (in this case) 100px from the top of screen (browser window). Alternatively, when div1 passes div2 (I'm using responsive design, so the fixed height from top might become a problem on smaller screens right? Seeing as the header for example won't be there on a hand held.). So maybe collision detection is better here? Would really appreciate some thoughts and input on this matter.
Another issue is, div2 has to revert back to is previous css once div1 passes it (going back (beyond the 100px)).
This is what I have but it has no effect
$(document).ready(function() {
var content = $('#div1');
var top = $('#div2');
$(window).on('scroll', function() {
if(content.offset().top <= 100) {
top.css({'opacity': 0.8});
}else{
top.css({'opacity': 1});
}
});
});
I am not sure of the reason but $("#content").offset().top was giving a constant value on console. So I added window.scrollTOp() to check its distance from top, here is how it works,
$(document).ready(function() {
var top = $("#menu");
$(window).on('scroll', function(){
if(($('#content').offset().top - $(window).scrollTop()) <= 100){
top.css({'opacity': 0.4});
}else{
top.css({'opacity': 1});
}
});
});
And DEMO JSFIDDLE....
I have been looking into parallax effects for vertical scrolling on my web page, and after some research, I'm not sure that what I want to do is technically a parallax effect.
From what I've seen, most parallax effects assume you want to be able to scroll indefinitely with many background images rolling by, or with huge images that repeat.
What I want to do is have the background of two DIVs be filled with a background image as the scroll bar reaches the bottom of the page. Note that I do not want the background images to stretch. I'm assuming to get the effect I want that these images would have a vertical height bigger than most people's viewport, and then their vertical position would change. When the user's scrollbar is at the top, a certain amount of the background is visible, and then it moves vertically to fill the background space as the user scrolls down.
Please see the image below for a visual explanation of the effect I hope to acheive:
The height of the veiwport will vary depending on the length of content inside the inner DIV.
My trouble is that if what I am trying to do is not exactly a parallax effect, then I don't know what else to call it, and my attempts to search by describing it keep landing me back at pages offering tutorials on parallax effects. So I've been stumped by a lack of terminology.
If someone could direct me to how I can control the vertical position of the background depending on the scrollbar position, that would be much appreciated. If this can be done with just CSS that would be great, but I'm assuming some Javascript would be required. A jQuery solution would also work for me.
Update:
After searching using the terms provided in comments, I've got the background image in the outer DIV to almost do what I want with the following code:
$(window).scroll(function () {
var yPos = $("#outerDiv").height() - ($("#outerDIV").height() * ($(window).scrollTop() / $(window).height()));
document.getElementById('outerDIV').style.backgroundPosition="0px " + yPos + "px";
});
It moves the background image in the right direction relative to the scrolling, but what it lacks is constraining that motion to within the viewport. Getting the right proportions based on the viewport and DIV sizes is proving to be just a little beyond my mathematical abilities.
For your requirement, you have to use a jquery parallax plugin to guide this activity, my best suggest it to use a Superscollorama and play with the elements as your wish...
As far as your question, Try this example,
controller.addTween(
'#examples-background',
(new TimelineLite())
.append([
TweenMax.fromTo($('#parallax-it-left'), 1,
{css:{backgroundPosition:"(0 -54px)"}, immediateRender:true},
{css:{backgroundPosition:"(0 -54px)"}}),
TweenMax.fromTo($('#parallax-it-right'), 1,
{css:{backgroundPosition:"(0 -54px)"}, immediateRender:true},
{css:{backgroundPosition:"(0 54px)"}})
]),
1000 // scroll duration of tween
);
You serial vice change as far as your wish...
Try practice this plugin, hope that works for you...
http://johnpolacek.github.io/superscrollorama/
Thanks...
Turns out what I want to acheive is possible with no special plugins, just some carefully thought out math. I did use a little jQuery syntax, but I don't think it's strictly necessary.
The code below has copious notes, so hopefully it's largely explanatory. In summary, you just need to find the position of the background image when the scroll would be at the top, and the position it would be if the scroll bar was at the bottom, and then you can use the percentage of the scrollbar's movement to work out where you are between those two points. It's a little tricker than just that, of course, in that you have to account for the difference between the total height of the scroll bar and where your DIV appears on the page and a few other adjustments, but the details of what I did are below.
What I've done here is just for the "outer DIV" that I described in my question. To get a background to move like the "inner DIV" I described, you'd have to modify the code, presumeably by reversing a few parameters. I haven't done that yet, but it seems like a straightforward task.
Hope others find this code useful. If anyone has suggestions on how it can be made more efficient or better, please let me know.
function moveBG(){
// imageHeight is not the total height of the image,
// it's the vertical amount you want to ensure remains visible no matter what.
var imageHeight = 300;
// Get the maximum amount within the DIV that the BG can move vertically.
var maxYPos = $("#outerDIV").height() - imageHeight;
// Get the amount of vertical distance from the top of the document to
// to the top of the DIV.
var headerHeight = document.getElementById("outerDIV").offsetTop;
// Calculate the BG Y position for when the scrollbar is at the very top.
var bgTopPos = $(window).height() - headerHeight - imageHeight;
// I don't want the image to wander outside of the DIV, so ensure it never
// goes below zero.
if (bgTopPos < 0)
{
bgTopPos = 0;
}
// Calculate the BG Y position when the scrollbar is at the very top.
var bgBottomPos = $(document).height() - $(window).height() - headerHeight;
// To prevent the BG image from getting cut off at the top, make sure
// its position never exceeds the maximum distance from the top of the DIV.
if (bgBottomPos > maxYPos)
{
bgBottomPos = maxYPos;
}
// Subtract the top position from the bottom, and you have the spread
// the BG will travel.
var totalYSpan = bgBottomPos - bgTopPos;
// Get the scrollbar position as a "percentage". Note I simply left it as a
// value between 0 and 1 instead of converting to a "true" percentage between
// 0 and 100, 'cause we don't need that in this situation.
var scrollPercent = ($(window).scrollTop() / ( $(document).height() - $(window).height()));
// The percentage of spread is added to the top position, and voila!
// You have your Y position for the BG image.
var bgYPos = bgTopPos + (Math.round(totalYSpan * scrollPercent));
// Apply it to the DIV.
document.getElementById('outerDIV').style.backgroundPosition="0px " + bgYPos + "px";
}
// Place the BG image correctly when opening the page.
$(document).ready(function() {
moveBG();
});
// Make it update when the scrollbar moves.
$(window).scroll(function () {
moveBG();
});
I do not know how to solve this situation:
I`ve got the html/css looks like this:
Image showing how my css/html looks like and what is displayed on the screen after landing on page:
The when I scroll down I see green element:
scrolling down ->
After continuing to scrolling down I saw full green element and the if I scroll down I want to have this element like in css language: position fixed bottom 0. See image below:
I ve saw full element -> same link but image called problem3.png
and then I scroll below and I want to have it fixed at the bottom of the page, like on this image:
Fixed element on screen - What I want and I do not know how to do that -> same link but image called problem4.png (stupid spam prevention mechanism)
Is it possible to solve this situation ?
To sum up: I`ve got two divs, one above and second below, Wheen I scroll down I suddenly see another element (green div) and when i continue to scroll down I WANT TO HAVE THIS GREEN DIV FIXED AT THE BOTTOM OF THE PAGE.
Ofcourse, when I scroll up (back on the top) I want to "park" that green div at the top of the second div.
Is there any way to solve this situation with jQuery (Javascript) / html / css ?
Thank you in advance
I think you'll have to show some of your html structure. There are lots of ways to achieve this kind of effect. Fundamentally, in javascript terms you'll be looking to:
Add an event listener to the window scroll that checks whether the green element is fully in view
If it is in view, add a class (or change it's css) that fixes it's position where you want
Change your window scroll method so that it's checking the relative offset of the red div to the top of the screen. If it goes below the position where the green div should be fixed, remove the class you added earlier.
That sounds complicated, but it's not too bad. The javascript would be something like:
$(function() {
$(window).scroll(function() {
if($(".divToFix").hasClass("fixedAtBase")){
if(Utils.underView($(".redDiv"), $(".divToFix").height())) $(".divToFix").removeClass("fixedAtBase");
} else {
if(Utils.inView($(".divToFix"))) $(".divToFix").addClass("fixedAtBase");
}
});
});
Utils = {
underView: function(element, offset) {
return (($(window).height() + $(window).scrollTop() - offset) <= element.offset().top);
},
aboveView: function(element) {
return ($(window).scrollTop() >= element.offset().top + element.height());
},
inView: function(element) {
return (Utils.aboveView(element) !== true && Utils.underView(element, element.height()) !== true);
}
};
Bear in mind I've not tested that or anything.
edit - here's a demo