scroll top on mobiles dont work smooth - javascript

I have made a function wich runs on the computer very well. But on mobiles the position refreshes only when the scrolling stops. Its a known problem and i found answers but I didnt get it in my function working. Maybe one of you can help me.
my function:
$(window).scroll(function () {
if ($(window).scrollTop() >600) {
$('#logo').css('position', "fixed");
$('#logo').css('top', 0);
}
else if($(window).scrollTop() < 600) {
$('#logo').css('position', "relative");
$('#logo').css('top', 600)
}
});
and in the internet i found this which i should replace in my function:
$('body').on({
'touchmove': function(e) {
console.log($(this).scrollTop()); // Replace this with your code.
}
});
or this:
$('body').bind('touchmove', function(e) {
console.log($(this).scrollTop()); // Replace this with your code.
});
It would be nice if someone could rewrite my function so that it works smoothly on mobiles.
I explain shortly what this function do. When you load my page there is a blackscreen with a headline in the middle of the screen. Nothing else. when you scroll down the title should move up normaly until he reaches the top. when it reaches the top it gets the "position: fixed" attribute. when you scroll up it gets the "position: relative" attribute again. Nothing else should happen. But on mobiles the text scrolls up until the scrolling stops (most of the time you scroll the text out of the screen) and pop up on the fixed position. But when it is fixed everything is ok and it stands there.

Related

Animate in div with image when scroll down to the bottom of where the image using jQuery

I have static images that I want to animate in when the user scrolls to the bottom of where they would be (the bottom of their rectangle). I've tried using the code:
$(window).on("scroll", function(){
if($("body").scrollTop() === 500){
$(window).off("scroll");
//Do stuff here
$('.context_right').fadein(4000);
}
});
With .context_right being the that contains the image I want to slide in from off the right side of the screen. I have tested this in Chrome debugger but there is not animation at all and I can't see why it's not being fired when scrolling down.
You're checking if the scroll position of the window is exactly equal to 500px. This is likely incorrect. You probably only want to check and see if the user has scrolled past 500px.
Consider changing:
if($("body").scrollTop() === 500)
to:
if($("body").scrollTop() >= 500)
Also, be careful with this:
$(window).off("scroll");
If you use any libraries that rely on the scroll event on the window, you would be unbinding all of those events in addition to your own.
Consider refactoring to something like the following:
var scrollAnimateIn = function(){
if($("body").scrollTop() >= 500){
$(window).off("scroll", scrollAnimateIn);
//Do stuff here
$('.context_right').fadein(4000);
}
};
$(window).on("scroll", scrollAnimateIn);

How to make Bootstrap header that changes size on scroll down?

I've seen a few different threads seemingly about this but none of the answers in them have a working solution for me.
Here's what I want:
Big transparent header with a big logo on the top.
Small colored header with a small logo when user has scrolled past the topmost area.
I'm using navbar-fixed-top and and Bootstrap's scrollspy to add and remove certain classes from the header.
Here's why it hasn't worked so far:
$(window).scrollTop() doesn't return anything meaningful at all.
It seems wrong to change at a certain amount of pixels from the top anyway, since it can vary between screen resolutions.
Initiating a change based on what activate.bs.scrollspy captures works rather well except it shows the wrong header when I load the page for the first time.
It seems impossible to place a <div id="whatever"> at a certain spot and have the header change when scrollspy finds it. I've tried making the div 1px in dimension and placed at the absolute top of the page, but the scrollspy still identifies it from way off.
Here's my jQuery code at the moment, which is very imprecise AND shows the wrong header at the first load of the page (remember, you're not always at the top of the page when loading (reloading) the page!).
$(document).ready(function() {
$('body').scrollspy({ target: '.navbar-inverse' });
$('#main-header').on('activate.bs.scrollspy', function () {
var currentItem = $('.nav li.active > a').text();
var header = $('.navbar');
var logosmall = $('.small-brand');
var logobig = $('.big-brand');
if (currentItem == 'top' && header.hasClass('navbar-small')) {
header.removeClass('navbar-small');
header.addClass('navbar-big');
logosmall.css('display', 'none');
logobig.css('display', 'inline-block');
}
else if (currentItem != 'top' && header.hasClass('navbar-big')) {
header.removeClass('navbar-big');
header.addClass('navbar-small');
logobig.css('display', 'none');
logosmall.css('display', 'inline-block');
}
});
});
Wrap your code into window scroll event as mentioned below then only $(window).scrollTop() will work as you expecting.
$(window).scroll(function () {});
Here is a great example of your problem, it is a bit tricky to shrink your navbar but not impossible. You have to take into account a lot of things. I found this a while ago: http://www.bootply.com/109943
It is really strange that $(window).scrollTop() does not return anything by the way. What browser are you on? And your problem with reloading the browser:
$(window).load(function{
//logic to check how far scrolled
})

Overflow Breaking ScrollTop / Not Registering Scroll

I have some CSS-driven parallax scrolling on my site, and I would also like to have a fixed top navigation bar appear when the user begins to scroll down the page. Currently, the nav bar only appears after you have scrolled PAST the end of the window (and disappears again when the window has "rubber banded" back into position). I'm using Chrome v38 on a Macbook. It looks like the overflow-x in my CSS is causing the scroll not to register/fire, but that's necessary for the parallax effect. Any help would be appreciated. Thanks.
CodePen example: http://codepen.io/anon/pen/jEPqYL (doesn't work exactly like in a browser, but that is my current code.)
My JS is:
(function($) {
$(document).ready(function() {
$(window).scroll(function() {
if ($(this).scrollTop() > 0) {
$('#header').fadeIn(500);
} else {
$('#header').fadeOut(500);
}
});
});
})(jQuery);

How to make this scrollTop function mobile-friendly

I have made a function wich runs on the computer very well. But on mobiles the position refreshes only when the scrolling stops. Its a known problem and i found answers but I didnt get it in my function working. Maybe one of you can help me.
my function:
$(window).scroll(function () {
if ($(window).scrollTop() >600) {
$('#logo').css('position', "fixed");
$('#logo').css('top', 0);
}
else if($(window).scrollTop() < 600) {
$('#logo').css('position', "relative");
$('#logo').css('top', 600)
}
});
and in the internet i found this which i should replace in my function:
$('body').on({
'touchmove': function(e) {
console.log($(this).scrollTop()); // Replace this with your code.
}
});
or this:
$('body').bind('touchmove', function(e) {
console.log($(this).scrollTop()); // Replace this with your code.
});
It would be nice if someone could rewrite my function so that it works smoothly in mobiles.
Edit
I explain shortly what this function do. When you load my page there is a blackscreen with a headline. Nothing else. when you scroll up the title should move up normaly until he reaches the top. when it reaches the top it gets the "position: fixed" attribute. when you scroll down it gets the "position: relative" attribute again. Nothing else should happen.
But on mobiles the text scrolls up until the scrolling stops (most of the time you scroll the text out of the screen) and pop up on the fixed position. But when it fixed everything is ok and it stands there.
The problem might be in the fixed position rather than in the scrollTop. Fixed positioned elements are not very mobile friendly.
Its behavior depends on the mobile device and OS.
More info: http://bradfrostweb.com/blog/mobile/fixed-position/

Change scrollTop offset

I am using bootstrap 3 and have a fullscreen hero unit at the top of my page, below that is my navigation. I have some js which allows my navbar to stick to be fixed at the top after you scroll past the full screen hero. Also some js for my smooth scrolling links.
The problem is the offset is different before you scroll past the full screen hero and after. But it works fine when you are past the jumbotron. I have tried a bunch of different things but I can seem to get this to work exactly.
Check out the fiddle here.
Here is my js for the smooth scrolling links:
$(document).ready(function() {
// navigation click actions
$('.scroll-link').on('click', function(event){
event.preventDefault();
var sectionID = $(this).attr("data-id");
scrollToID('#' + sectionID, 750);
});
// scroll to top action
$('.scroll-top').on('click', function(event) {
event.preventDefault();
$('html, body').animate({scrollTop:0}, 1200);
});
// mobile nav toggle
$('#nav-toggle').on('click', function (event) {
event.preventDefault();
$('#main-nav').toggleClass("open");
});
});
// scroll function
function scrollToID(id, speed){
var offSet = 95;
var targetOffset = $(id).offset().top - offSet;
var mainNav = $('#main-nav');
$('html,body').animate({scrollTop:targetOffset}, speed);
if (mainNav.hasClass("open")) {
mainNav.css("height", "1px").removeClass("in").addClass("collapse");
mainNav.removeClass("open");
}
}
if (typeof console === "undefined") {
console = {
log: function() { }
};
}
By changing var offSet = 95; I am able to adjust the offset but what would be the best way to use 180 before the navbar sticks to the top but 95 when it does?
Also here is the js I am using for my navbar:
$(function () {
/* $(".navbar-fixed-top").css({"top":$(".jumbotron").height()});
$(window).resize(function (e) {
$(".navbar-fixed-top").css({"top":$(".jumbotron").height()});
});*/
$(document).on( 'scroll', function(){
console.log('scroll top : ' + $(window).scrollTop());
if($(window).scrollTop()>=$(".jumbotron").height())
{
$(".navbar").addClass("navbar-fixed-top");
}
if($(window).scrollTop()<$(".jumbotron").height())
{
$(".navbar").removeClass("navbar-fixed-top");
}
});
});
Are you open to angular.js? I have a directive i use for this. As seen here.
I'll grab the plunker link for you. you might find the code helpful.
Essentially you need to create a ghost dom element to take the place of the menu when you pull it to an new layout position.
EDIT: Here it is
I won't suggest grabbing angular just for this. But you can use the basis of the events and logic to build your own solution.
This here is creating an element and placing in its place
$scope.spacer = $element.after(
'<div class="spacer" style="height:' + $element[0].clientHeight + 'px"> </div>').next();
then this element is removed when the menu is back to its static position.
Inspect the dom and watch how it changes, this will probably help you see the events and changes that need to take place.
EDIT 2 SOLUTION:
HERE is the concepts applied to your JSFiddle
It's not the best solution but by adding margin: 0 0 -100px 0; to your .navbaryou lose the spacing issue.
Also you're getting 22 console errors because of missing images. I'm not saying that this is causing any major problems but you would be better off losing them.
The problem is that when you have not scrolled past the hero, navigation is still part of the layout and pushes content bellow it a little lower. When you scroll past (either manually or via a script) the hero, navigation is removed and fix positioned. That makes everything which was bellow to "jump up" exactly of the navigation height.
That means if portfolio was 1000px from the top, on click you say: go 1000px from top; but then porfolio moves 100px up (as explained above) meaning it is now 900px from the top while the window scrolled 1000px as you asked.
When you have scrolled past the hero, nothing changes its position.

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