I'm trying to have my content fade in when reaching a certain proximity to to respective ends of the page. The fade works fine when the trigger is set to the very top and bottom but when I set a distance (200px) the fade no longer works and the content simply appears.
$(window).scroll(function(){
if($(window).scrollTop()<=200){
$('#about .content').stop(true,true).fadeIn("5s");
}
else {
$('#about .content').stop(true,true).fadeOut("10s");
}
if ($(window).scrollTop() + $(window).height() >= $(document).height() - 200) {
$('#work .content').stop(true,true).fadeIn("5s");
} else {
$('#work .content').stop(true,true).fadeOut("5s");
}
});
What is happening is that you have two functions working against each other:
The first function has an "if-else" statement and the second function as well.
That means that each function does something EVERYTIME you scroll.
There are multiple ways of solving this.
The way I would solve it is using a variable and updating the constraints.
Let's say we have a variable onScreen that has value 1 if the paragraph is on the screen and value 0 if it isn't:
For example:
<div style="height: 800px">Example of scroll with fadeIn, fadeOut.
<p style="margin-top:300px;">These paragraphs will go away when you have scrolled
more than 10 pixels from the top. They will appear again when you have scrolled
to a proximity of 50 pixels from the bottom. They will also appear if you go
within a proximity of 10 pixels of the top again.</p>
</div>
Now for the jQuery code:
var $onScreen = 1;
$(window).scroll(function(){
if($(window).scrollTop() < 10){
if ($onScreen == 0)
{
$("p:first").stop(true,true).fadeIn("slow", "linear");
$onScreen = 1;
}
}
if($(window).scrollTop() <= 20 && $(window).scrollTop() >= 10){
if ($onScreen == 1)
{
$("p:first").stop(true,true).fadeOut("slow", "linear");
$onScreen = 0;
}
}
if ($(window).scrollTop() + $(window).height() >= $(document).height() - 50) {
if ($onScreen == 0)
{
$("p:first").stop(true,true).fadeIn("slow", "linear");
$onScreen = 1;
}
}
});
Now this is not the most concise way of doing it and I didn't mean to do so: by making the code a bit more extensive I hope you can follow why it works now and didn't work before (such that you actually learn from it).
I prepared a live example for you on Fiddle: http://jsfiddle.net/ycCAb/4/
I hope this answers your question. Good luck!
Related
I want to create an animation where with scrolling background image of the Website changes. Changing happens with a fadeIn and fadeOut effect, But fading effect happens multiple times due to scroll function.
JSFiddle
Jquery Code:
var styles01 = {"background" : "url(https://iso.500px.com/wp-content/uploads/2016/02/cover.jpg) fixed",
"background-size":"cover"};
var styles02 = {"background" : "url(http://www.mybligr.com/wp-content/uploads/2017/02/beautiful-lake-wallpaper-nature-photos-pics-images-pictures-16.jpg) fixed",
"background-size":"cover"};
var styles03 = {"background" : "url(https://cdn.fodors.com/ee/files/slideshows/9-derwent-water-lake-district-england.jpg) fixed",
"background-size":"cover"};
$(window).scroll( function() {
if ($(window).scrollTop() >= 50 && $(window).scrollTop() <= 150) {
$(".wrap").fadeOut(200);
$(".wrap").css(styles01);
$(".wrap").fadeIn(200);
}
if ($(window).scrollTop() >= 150 && $(window).scrollTop() <= 250) {
$(".wrap").fadeOut(200);
$(".wrap").css(styles02);
$(".wrap").fadeIn(200);
}
if ($(window).scrollTop() < 50) {
$(".wrap").fadeOut(200);
$(".wrap").css(styles03);
$(".wrap").fadeIn(200);
}
});
It appears to be a timing issue, because you're trying to re-style and re-fade before the initial fade-out is done. This is an asynchronous operation:
$(".wrap").fadeOut(200);
So anything that needs to happen after this operation should be placed in its callback, not placed immediately after this line of code. Something like this:
$(".wrap").fadeOut(200, function () {
$(".wrap").css(styles01);
$(".wrap").fadeIn(200);
});
Updated fiddle.
I am making a website but I don't know much about javascript or jquery. I have a down arrow on my homepage showing that there is more information but I want it to go away when the user scrolls to the bottom of the page because it is then not needed because they can't scroll down anymore. I know I will need javascript or jquery to do this but I don't even know where to start with it. Help!
Try something like this :
document.onscroll = function() {
if (window.innerHeight + window.scrollY > document.body.clientHeight) {
document.getElementById('arrow').style.display='none';
}
}
Where 'arrow' is the id of the image.
Using jquery:
$(window).scroll(function(){
var numPix = 200; // number of pixels before bottom of page that you want to start fading
var op = (($(document).height() - $(window).height()) - $(window).scrollTop()) / numPix;
if( op <= 0 ){
$("#thing-to-hide").hide();
} else {
$("#thing-to-hide").show();
}
$("#thing-to-hide").css("opacity", op );
});
Hello! I've been learning jQuery for a little while now and am trying to sharpen my skills by creating a responsive website. I added a navigation bar, then a big slider, and below it is the main content of the website. Right now, jQuery (as both the menu background and the main background are black) adds a class to the navigation bar in order to turn it white as soon as you scroll past the slider (which has a height of 550px), so it will be easier to read.
Here's the thing: I want jQuery to add that class depending on the width of the window. If it's less than 600px wide, I want the class to be added automatically. Otherwise, I want jQuery to add it as soon as you scroll past the slider (since I hide it when the window is less than 600px wide). My code is below, and it works just fine if I resize the window and then refresh the page, but I want it to add the class dynamically. Do you think it is possible?
I hope I made myself clear (English is not my first language). Let me know if you need me to explain things better! Thank you in advance. :)
if ($(window).width() > 599 ) {
$(window).scroll(function() {
if ($(window).scrollTop() >= 550) { //if you scroll past the slider
$("#main nav").addClass("white-menu");
} else {
$("#main nav").removeClass("white-menu"); //so it turns black again
}
});
} else {
// add it automatically (the slider is hidden):
$("#main nav").addClass("white-menu");
};
you can use all the code inside scroll event
$(window).scroll(function() {
if ($(this).scrollTop() >= 550 && $(this).width() <= 599) { //if you scroll past the slider
$("#main nav").addClass("white-menu");
} else {
$("#main nav").removeClass("white-menu"); //so it turns black again
}
});
a similar DEMO
about resize you can use
$(window).on('resize',function() {
$("#main nav").removeClass("white-menu");
});
on window resize the code will remove the class till user scroll then the scroll event will fire after user scrolling
or instead of all of that you can just use
$(window).on('scroll resize',function() {
if ($(this).scrollTop() >= 550 && $(this).width() <= 599) { //if you scroll past the slider
$("#main nav").addClass("white-menu");
} else {
$("#main nav").removeClass("white-menu"); //so it turns black again
}
});
DEMO
.scroll allows you to listen to event, if you only listen when the window is the correct size, this listener won't get triggered if that changes, so I changed it around a bit:
$(window).scroll(function() {
if ($(window).width() > 599 ) {
if ($(window).scrollTop() >= 550) { //if you scroll past the slider
$("#main nav").addClass("white-menu");
} else {
$("#main nav").removeClass("white-menu"); //so it turns black again
}
}
});
Like Brian mentioned you should use CSS for this other case:
#media (max-width: 600px) {
#main nav {
// white-menu styles here
}
}
For reference the JS way would be:
$(window).resize(function() {
if ($(window).width() <= 599 ) {
$("#main nav").addClass("white-menu");
}
});
It also might be worth thinking about doing a throttle/debounce on these event listeners. They will get called a lot and if your JS starts to do anything more complicated you will see a performance hit. This example uses the underscore library:
var onScroll = function() {
if ($(window).width() > 599 ) {
if ($(window).scrollTop() >= 550) { //if you scroll past the slider
$("#main nav").addClass("white-menu");
} else {
$("#main nav").removeClass("white-menu"); //so it turns black again
}
}
}
// Don't run until the window has stopped being resized for at least 50ms
var debouncedOnScroll = _.debounce(onScroll, 50);
$(window).scroll(debouncedOnScroll);
See http://underscorejs.org/#debounce
Interesting. I used your code in a fiddle and it worked find. As it's state in another answer, the improve of your code will be using the scroll function to wrap all the actions:
$(window).scroll(function() {
$("#main nav").toggleClass("white-menu", ($(window).scrollTop() >= 550 && $(window).width() <= 599));
});
I've been trying to fade out a splash when scrolling down, and fading it in when scrolling back to the top of the page. It seems to work ok when scrolling down, but when I go back, it doesn't fades in. I tryed using fadeIn and FadeOut instead of fadeTo but didn't get a proper behavior
The code is actually pretty simple:
var splashTop = $('.splash-container').offset().top;
$(window).scroll(function () {
if ((splashTop - $(window).scrollTop()) < 50) {
$('.splash-container').stop().fadeTo("slow", 0);
} else {
$('.splash-container').stop().fadeTo("fast", 1);
}
});
And here is the jsFiddle example:
jsFiddle
If you just need to check if the scroll is at the top or not then you don't need to check the position of the Splash, Try:
$(window).scroll(function () {
if ($(window).scrollTop() > 0) {
$('.splash-container').stop().fadeTo("slow", 0);
console.log('p')
} else {
$('.splash-container').stop().fadeTo("fast", 1);
console.log(box1Top)
}
});
Check the Demo Fiddle
Edit
Now why your code doesn't work? ... Because you are always getting a value less than 50:
splashTop = 8 always
-
$(window).scrollTop() = more than 0
Then the result is always negative or 8 as max, you can never have a number more than 8 and your else condition is useless.
I'm using the following javascript for the top of page logo/section before the footer here:
<div id="townEnd">InsideTown</div>
<script>
$(document).ready(function(){
// hide #townEnd first
$("#townEnd").hide();
// fade in #townEnd
$(function () {
$(window).scroll(function () {
if ($(this).scrollTop() > 1000) {
$('#townEnd').fadeIn();
} else {
$('#townEnd').fadeOut();
}
});
// scroll body to 0px on click
$('#townEnd a').click(function () {
$('body,html').animate({
scrollTop: 0
}, 800);
return false;
});
});
});
</script>
How would I calculate when the logo should fadein at the end of the page? I just used 1000 as an example. It only seems to work when I scroll really fast too.
First, you should just use this.scrollTop instead of $(this).scrollTop() - it might not look like much to you, but it is a HUGE thing.
On the same path, you can use this.scrollHeight to get the height of the scrollable area. Subtract this.innerHeight to get the maximum scroll position, then subtract about 30 pixels to give yourself some padding.
if( this.scrollTop < this.scrollHeight - this.innerHeight - 30)
You should also have a boolean to keep track of the state of the element, maybe isfadedin, which you update. Then, only call fadeIn and fadeOut if the state changes. This will save a LOT of processing time!
Vanilla JS is awesome :p