I'm trying to display a div after scroll animation has finished and hide it when I scroll up/down the page. This is my attempt:
$('#cta').on('click', function(e) {
e.preventDefault();
$('#layer, #servicesContent').addClass('active');
var position = parseInt($('#services').offset().top);
$('html, body').animate({
scrollTop: position - 100
}, 'slow', function() {
$(window).bind('scroll', function() {
$('#layer, #servicesContent').removeClass('active');
});
});
});
it doesn't work. the active class is removed after animation has finished and not with scroll movement.
Any idea?
Thanks in advance
Not exactly sure why, but apparently it takes the window somewhere around 20 milliseconds to exit the scroll state, at least on Chrome, on Windows. Or it might be a jQuery trick to fire the animation function 20ms sooner, so it feels more natural. (Human eye and mind make connections that take tiny amounts of time and maybe they took it into account).
Anyway, in order to make sure you bind after the scroll has ended, give it a full 100ms to finish and bind afterwards:
$('#cta').on('click', function(e) {
e.preventDefault();
$('#layer, #servicesContent').addClass('active');
var position = 120;
$('html, body').animate({
scrollTop: position - 100
}, 'slow', function() {
setTimeout(function(){
$(window).bind('scroll', function() {
$('#layer, #servicesContent').removeClass('active');
});
},100)
});
});
working fiddle.
Please note I had hard-coded a value to position, as #services is not defined in my example.
Also please note that hiding events on scroll is a really bad idea in terms of usability. Users might want to scroll so they view the div better or read it in full, but they will end up hiding it, which would be annoying. I would at least check the scroll event for a minimum velocity or distance in order to hide an element from the screen.
Related
I'm currently trying to get my navigation bar (fixed at the top of the screen) to work better. Currently, if you press on a link within the nav bar, it will go to a certain section with this code:
$('a[href^="#"]').bind('click.smoothscroll',function (e) {
e.preventDefault();
var target = this.hash,
$target = $(target);
$('html, body').animate({
'scrollTop': $target.offset().top - 45
}, 400, 'swing', function () {
window.location.hash = target;
});
});
});
However, it will go to that section but then shift down on the screen and cover content. But if I press the same section again, it will go to the correct spot. I need it to go to the correct spot on the first click.
When I take out the "- 35" part within animate(), it doesn't shift down and goes smoothly, but I need the "- 35" part to offset the nav bar or else it will cover content every time. What is causing this jumping/shifting? Any advice or information that would be helpful? Thanks!
Note: I also have this code, but I'm not sure if it's part of the issue:
$(document).ready(function(){
var offset = $(".navbar").offset().top;
$(window).scroll(function() {
if ($(window).scrollTop() >= offset) {
$('.navbar').addClass('navbar-fixed');
}
});
UPDATE: I fixed my issue by reading more into the details of jQuery's animate. The parameter "complete" (a function to call once the animation is complete, called once per matched element) that I was using was not necessary, so I removed it from my code.
You need to avoid setting the hash after the animation is completed. As you use an offset for the animation (the -45) the animation will run smoothly to the given coordinates, and then it will jump to the hash position when you set the location.hash (after the animation is completed). The solution is to remove the hash from the location (the preventDefault() does that), and don’t set it again after animation is completed.
$('a[href^="#"]').bind('click.smoothscroll',function (e) {
e.preventDefault();
var target = this.hash,
$target = $(target);
$('html, body').animate({
'scrollTop': $target.offset().top - 45
}, 400, 'swing');
});
I have arrows in the center of my web pages at the end of sections and I was these to allow users to scroll to the next section on click. I have the following code where the first click works but subsequent clicks do not scroll even though the function is being called each time.
$('.scroll').on('click', function(event) {
alert('scroll');
$('html, body').animate({
scrollTop: $(".scroll").offset().top
}, 1000);
});
Can anyone assist? https://jsfiddle.net/avL459sm/2/
You should use current .scroll element you clicked on.
Look at this fiddle: https://jsfiddle.net/avL459sm/3/
I have it set to a div's width increases when I scroll past it with the following code. Now I do this same thing except with .fadeIn() and it works fine. But when I use the .animate() i'll scroll to that location and nothing will happen, but like randomly 30-40 seconds later it will just decide to animate without me even touching/moving anything. Any reason why that is?
HTML
<div>
2500px of CONTENT
</div>
<div class="statbar"></div>
CSS
.statbar {
width:100px;
height:30px;
background-color:#ff4200;
}
jQuery
$(document).scroll(function () {
var y = $(this).scrollTop();
if (y > 2500) {
$('.statbar').animate({width:'200px'}, 300);
} else {
$('.statbar').animate({width:'10px'}, 300);
}
});
Here's a JSFiddle example: https://jsfiddle.net/kr4yeyw3/2/
If you wait like 30 seconds at the div, you'll see the animation will take place (need it to happen instantly like the fadeIn() does.
EDIT: It works when I change those 300 to zeros, but it doesn't animate! Just changes width instantly without "sliding" it over.
EDIT2: Finally figured it out for anyone who one day scrolls across this page looking for a similar answer.
Adding clearQueue(), stop() and easing seemed to do the trick
$('.statbar').clearQueue().stop().animate({width:'75%'}, { "duration": 400, "easing": "linear" });
clearQueue or Stop will do fix the animation, but it doesn't address the real problem with your code. In your else statement, which is hit like 2000 times as you scroll to the bottom of the page, you are starting an animation with a duration of 400 milliseconds.
jQuery animate puts all animations into a queue and calls them one after the other so it creates a huge delay before the animation you actually want to see. api.jquery.com/animate/
Here's how I think you should rework your code:
var isExpanded = false;
$(document).scroll(function () {
var y = $(this).scrollTop();
if (y > 2500) {
$('.statbar').animate({width:'200px'}, 300);
isExpanded = true;
} else if(isExpanded) {
$('.statbar').animate({width:'10px'}, 300);
isExpanded = false;
}
});
Here I use a flag to determine if the animation needs to be run and just toggle it as we switch display modes.
I want to achieve some kind of smooth scrolling, so I made this script:
$('a').click(function(){
var sclink = $(this).attr('href');
$('.menu').animate({
scrollTop: $(sclink).offset().top
}, 500);
return false;
});
The problem? When I click on the 'a' the offset.top() value changes in another weird value and toggle between them? Why does this happen and how do I resolve it?
http://jsfiddle.net/StartStep/9SDLw/2947/
I think the problem is with the scroll.top() that gets the value in another way...
jsfiddle.net/9SDLw/2950/
$('a').click(function(){
var sclink = $(this).attr('href');
$('.menu').animate({
scrollTop: $(sclink).position().top
}, 500);
logit('Anchor: '+sclink+'; Offset top value: <b>'+$(sclink).offset().top+'</b>')
return false;
});
Use position instead of offset.
The reason is offset is relative to the viewport, as such it looks like you've scrolled too far, but this is because the top of your viewport area is being obscured by your layout, so offset is actually not what you want, instead, position is.
You should also add a reference to stop before calling animate to ensure if a user clicks in quick succession the behaviour is as expected (the animation queue is essentially flushed)
With that in mind your HTML also needs some work- the clickable link hasnt got closing tags for example.
Change your scrolling code to:
$('.menu').stop(true,true).animate({
scrollTop: $(sclink).position().top
}, 500);
Demo Fiddle
Why does another scroll event get called after a scrollTop animation fires its complete callback?
Click Handler:
var lock = false;
$('#id').click(function(event) {
var pos;
if (lock) {
return;
}
lock = true;
pos = 150;
console.log("jump start");
$(jQuery.browser.webkit ? "body": "html").animate({ scrollTop: pos }, 150, function () {
lock = false;
console.log("jump end");
});
});
Scroll Handler:
$(window).scroll(function (e) {
console.log("scrolling");
if (!lock){
alert('1');
}
});
Log:
jump start
scrolling
jump end
scrolling
demo on jsfiddle
Background
jQuery scrollTop() uses scrollTo() which is a fire and forget event. There is no stopped event for scrolling. The scroll events occur out of band from scrollTo. scrollTo means 'start scroll', a scroll event means 'scrolled (some position)'. scrollTo just initiates the starting of the scroll, it doesn't guarantee that scrolling finished when it returns. So, jQuery animation completes before final scroll (there could even be multiple scrolls backed up). The alternative would be for jQuery to wait for the position of the scroll to be what it requested (per my soln), but it does not do this
It would be nice if there was a specification that we could point to describing this, but it is just one of the Level 0 dom elements without a spec, see here. I think it makes sense the way that it works, which is why all browsers seem to implement it this way.
Why is this happening
The following occurs on the last scroll of the animation:
jquery: 'Window please scroll this last bit'
Window: 'I got this message from jquery to scroll I will start that now'
jquery: 'woohoo I am finished the animation, I will complete'
Your code: lock = false;console.log("jump end");
Window: 'I have scrolled' call scroll event handlers.'
Your code: $(window).scroll(function (e) { 'Why is this happening?'
As you can see jquery does not wait for the final scroll step of the animation to complete before completing the animation (going on to step 4). Partly this is because there is no stopped event for scrolling and partly this is because jquery does not wait for the scroll position to reach the position that was requested. We can detect when we have reached the destination position as described below.
Solutions
There is no stopped event for when scrolling completes. See here. It makes sense that there is no stopped event because the user could start scrolling again at any point, so there is no point where scrolling has really stopped - the user might just have paused for a fraction of a second.
User scrolling: For user scrolling, the normal approach is to wait some amount of time to see if scrolling is complete as described in the answer of the referenced question (bearing in mind that the user could start scrolling again).
scrollTop: However, since we know the position that we are scrolling to we can do better.
See this fiddle.
The crux of it is that since we know where we are scrolling to, we can store that position. When we reach that position we know that we are done.
The output is now:
jump start
scroll animation
jump end
The code is (note that this is based off your fiddle rather than the code in the edited question):
var scrollingTo = 0;
$('#id').click(function(event) {
if (scrollingTo) {
return;
}
console.log("jump start");
scrollingTo = 150;
$(jQuery.browser.webkit ? "body": "html").animate({ scrollTop: scrollingTo }, 150, function () {
});
});
function handleScroll()
{
if( scrollingTo !== 0 && $(window).scrollTop() == scrollingTo)
{
scrollingTo = 0;
console.log("jump end");
}
}
$(window).scroll(function (e) {
if (!scrollingTo){
console.log('user scroll');
} else {
console.log("scroll animation");
}
handleScroll();
});
I believe that at the time the animation ends and the callback function is called, the event has not reached the window yet, so it is not re-called, it just hasn't been fired yet.