Javascript Scroll Animation Issue - javascript

I attempted to make an animation, so that a header and a paragraph will increase in size when a user has scrolled to it. When the user scrolls past the header, the text will shrink back.
I had an issue getting this to work, but I got it after looking at: Animate on scroll with jQuery
However, the font increases jerkily when I scroll down. Oddly, it works better when I scroll up.
Here is the code:
$(document).ready(function () {
$(document).on("scroll", onScroll);
function onScroll(event){
$('#sched li').each(function () {
var scrollPos = $(window).scrollTop()+250;
var currLink = $(this);
var refElement = currLink.find("div");
if (refElement.offset().top <= scrollPos && (refElement.offset().top+refElement.height())>scrollPos){
currLink.find("h1").stop().animate({fontSize:'40px'},300);
currLink.find("p").stop().animate({fontSize:'30px'},300);
currLink.addClass("active");
}
else{
if(currLink.hasClass("active")){
currLink.find("h1").stop().animate({fontSize:'20px'},300);
currLink.find("p").stop().animate({fontSize:'15px'},300);
currLink.removeClass("active");
}
}
});
}
});
I am somewhat new to this, so any help would be appreciated.

Related

Navbar change on scroll and on window load or resize

I have this issue that I'm not being able to work correctly.
I have a navbar that must change on scroll(this part works fine) but it must also change when window/viewport is < 991px.
It actually does work, but I must scroll to apply the effect.
Here's my code:
$(document).ready(function()
{
var $navbar = $('.navbar');
// ----------
$(function()
{
$(window).scroll(function()
{
if(($(window).scrollTop() > 60 && $(window).on('load resize').width() > 992) || ($(window).on('load resize').width() < 992))
{
$navbar.addClass("compressed");
}
else
{
$navbar.removeClass("compressed");
}
});
});
});
If I shrink the broswer, nothing happens. At the first scroll, it works correctly. How should I trigger it when load or resize the window?
Thanks!
Just replace this:
$(window).scroll(function() {...});
with this:
$(window).on("load scroll resize", function() {...});
That will result in the function being called on any of the listed events.

jQuery -- Prevent User from Scrolling Up Past Certain Scroll Height

I am making a one-page website.
Basically, I have this animated landing page with a landing image and a bootstrap jumbotron. I want to be able to implement a function where once the user scrolls past the end of the jumbotron, the user cannot scroll back up to view the landing image and the jumbotron. In a sense, either hide or delete the <div>s that were at the top, or completely disable scrolling back to those points.
I found this code, but it automatically disables scrolling up to the page top (after 200 px) on page load:
$(function() {
var scrollPoint = 200;
$(window).scroll(function() {
$(window).scrollTop() < scrollPoint ?
$(window).scrollTop(scrollPoint) : '';
}).scroll();
});
Any ideas?
You can use this code to hide the jumbotron.
$(window).bind('scroll', function() {
if($(window).scrollTop() >= $('#id_of_jumbotron').offset().top +
$('#id_of_jumbotron').outerHeight() - window.innerHeight) {
hideTheJumboTron();
}
});
try this:
$(function () {
var scrollPoint = 200;
$(window).scroll(function () {
if ($(window).scrollTop() < scrollPoint) {
console.log($(window).scrollTop());
$(window).scrollTop(scrollPoint)
return false;
}
}).scroll();
});

Sticky Navigation not working

I'm trying to add a 'fixed' class to a menu once the scroller hits that menu. I've managed to get it working, but having problems removing the class once the user scrolls back to the top.
Here is the site I'm working on: http://www.allbyor.com/
Here's is my JS code:
$(window).bind('scroll', function () {
var menu = $('.bottom-row');
if ($(window).scrollTop() >= menu.offset().top) {
menu.addClass('menufix');
} else {
menu.removeClass('menufix');
}
});
You need to register the original value of the menu.offset().top in a variable, because once you change its class to fixed the top value will be the same as the $(window).scrollTop().
JSFiddle demo.
var menu = $('.bottom-row');
var menu_top_value = menu.offset().top;
$(window).bind('scroll', function () {
if ($(window).scrollTop() >= menu_top_value) {
menu.addClass('menufix');
} else {
menu.removeClass('menufix');
}
});

jQuery Scrolling Length

I am working with a script to scroll an element on click. It's working properly, however it either scrolls all the way up, or all the way down. I'm new to jquery, and I'm wondering how to make it scroll a little at at time. For example, clicking to scroll down once will take you down a certain length, clicking again scrolls that length again. Also, sometimes it jitters and bugs out when scrolling back up. Any insight on how to fix this is appreciated as well!
Thanks.
Code below:
<script type="text/javascript" src="http://code.jquery.com/jquery-1.4.4.min.js"></script>
<script>
$(function() {
var ele = $('#scroll');
var speed = 25, scroll = 5, scrolling;
$('#scroll-up').click(function() {
// Scroll the element up
scrolling = window.setInterval(function() {
ele.scrollTop( ele.scrollTop() - scroll );
}, speed);
});
$('#scroll-down').click(function() {
// Scroll the element down
scrolling = window.setInterval(function() {
ele.scrollTop( ele.scrollTop() + scroll );
}, speed);
});
$('#scroll-up, #scroll-down').bind({
click: function(e) {
// Prevent the default click action
e.preventDefault();
},
mouseleave: function() {
if (scrolling) {
window.clearInterval(scrolling);
scrolling = false;
}
}
});
});
</script>
You're saying you want to scroll little at a time but your code is saying scroll UNTIL mouse leaves. If you want to scroll little at a time why would you write a mouseleave which clearly stating if it's been scrolling stop now!
If you want to scroll up/down a bit on click, you should get rid of setInterval and mouseleave.
$(function() {
var ele = $('#scroll');
var speed = 25, scroll = 5;
$('#scroll-up').click(function() {
// Scroll the element up
ele.scrollTop( ele.scrollTop() - scroll );
});
$('#scroll-down').click(function() {
ele.scrollTop( ele.scrollTop() + scroll );
});
$('#scroll-up, #scroll-down').bind({
click: function(e) {
// Prevent the default click action
e.preventDefault();
}
});
});
jsfiddle

How to scroll page on multiple ID in js

Please check what i did yet http://jsfiddle.net/dUVmh/1/ .
About the animation i want to achieve is that:
When you first scroll down the page then window scroll to #green DIV. After that if you again scroll down window scroll to #yellow DIV & same at the time of scrollup (fom #yellow to #green).
About the issue:
You can see the animation it's stuck on #green DIV.
$(window).scroll(function(){
if($(this).scrollTop() > 0) {
$("html, body").animate({ scrollTop: $('#green').offset().top }, 1000);
}
else if($(this).scrollTop() > 1000) {
$("html, body").animate({ scrollTop: $('#yellow').offset().top }, 1000);
}
else{
$("html, body").animate({ scrollTop: $('#red').offset().top }, 1000);
}
});
I didn't have much experience in JS.
Thanks i advance :)
This was a fun problem to work on.
This solution places the divs into an array, and remembers the array index of the element that was last scrolled to. Once a scroll event is triggered it checks to see if the new scrollTop is above or below the current divs top offset and moves to the next or previous div in the array accordingly.
This solution allows you to have many divs. I tried to remove the flickering you get when you scroll to fast, but the only way to do that I believe would be to disable the scrollbars during animation.
http://jsfiddle.net/dUVmh/35/
$(function() {
var divs = [],
body = $('body, html'),
currentDiv = 0,
timeout;
$('div').each(function() {
divs.push($(this));
});
// we only need to capture the first scroll event triggered and then
// add another listener once we have done our animation
var scrollListen = function() {
$(window).one('scroll', function() {
doScroll($(this).scrollTop());
});
};
// Without the timeout, the scroll event would be triggered again too soon
var scrollEnd = function() {
clearTimeout(timeout);
timeout = setTimeout(function() {
scrollListen();
}, 10);
};
// checks if the scroll direction was up and down and animates
// the body scrollTop to the next or previous div
var doScroll = function(scrollTop) {
var direction = scrollTop - divs[currentDiv].offset().top;
if (direction > 0 && currentDiv + 1 < divs.length) {
nextDiv = currentDiv + 1;
} else if (currentDiv - 1 > -1) {
nextDiv = currentDiv - 1;
}
if (currentDiv === nextDiv) {
scrollEnd();
}
body.animate({
scrollTop: divs[nextDiv].offset().top
}, 1000, function() {
currentDiv = nextDiv;
scrollEnd();
});
};
scrollListen();
});
Edit: Firefox scrollTop required to be changed on html and not body. Also fixed a problem with firefox calling scrollListen more than once at a time.
The problem is that the $(window).scroll(function()) gets called over and over again when scrolling through the ScrollTop animation with jQuery.
Here is a possible solution that checks if it is currently scrolling or not and only executes the ScrollTop animation once.
http://jsfiddle.net/dUVmh/29/
Side note: It might be a good idea to check which direction the user is scrolling (up or down) and depending on that scroll to the next div to the top or to the down.
You can check that be saving the last scrollTop position and comparing it with the current one.
UPDATE: Here's a solution that takes the scroll direction into account: http://jsfiddle.net/dUVmh/36/

Categories