I'm making a navigation bar that remains at the top of the page. When the user scrolls down, this bar will shrink, and when the user goes back to the top of the page, the navbar returns to its original dimensions.
Problem: When the user scroll down, the navbar shrinks as expected. However if the user scrolls back to the top of the page quickly, the navbar remains shrunken, and the animate() function within the scrollTop() callback function triggers after a few seconds.
To debug this, I included console.log($(window).scrollTop()); to tell me the current position of the user on the page. I get the console.log output as quick as the user scrolls. But {console.log('animated'); which is supposed to fire when the animation is completed, does not appear till a few seconds later after console.log($(window).scrollTop()); outputs 0.
How can I get animate() to respond quickly when the user scrolls up?
JS Code
var navBar = $('#navbar-inner');
var top = navBar.css('top');
$(window).scroll(function() {
console.log($(window).scrollTop());
if($(this).scrollTop() > 50) {
navBar.animate({'marginTop':'-20', 'height':'60'}, 300);
} else {
navBar.animate({'marginTop':'0', 'height':'80'}, 300, function()
{console.log('animated');});
}
});
(Posting my comment as an answer)
Use .stop() to stop any ongoing animations before starting a new one.
I experienced this kind of issues before with animations that last longer than the user action. You just need to stop the animation, something like
navBar.stop(true, true).animate(...);
To understand stop() better here is the link http://api.jquery.com/stop/. Hope it helps
Related
I am using the window.scrollY event listener to get the scroll amount on my page and I set an animatino fram accordingly:
scroll = window.scrollY //inside the event listener
...
function animationLoop() {
...
scrollRatio = scroll/window.innerHeight
animMixer.setTime(scrollRatio) // every page is a "second"
...
}
This works wonderfully on the desktop, and also on iOS on the first scroll forward through the page. But as soon as the page bounces at the end, the scroll value seems to jump around unnecessarily, ie there is a mismatch between the position in the webpage and the animation frame. The timing is off until I scroll back to the very top of the page. After that the downward scrolling works fine again.
What happens to the scrollY value after bounce? I can't figure out where the problem is. I've tried things like pageYOffset but the problem remains. Also the value of the scrollRatio is clamped.
I know that there are some issues with the bouncy behavior of webpages on iOS, but these are negative values at the top of the page.
Thanks for any pointers.
I've recently taken over work on a friend's website, here. I want to get the small logo above the description box to only show up once the user has scrolled past (and subsequently hidden) the large header at top, and disappear again if the user scrolls back up past it. I've tried the methods recommended in these other posts here and here, which seem like the same basic idea but I can't get any of them to work.
I'm new to anything and everything scripting (which I'm entirely sure is the biggest problem here, I know.) So any help is appreciated as what I'm apparently doing wrong.
Start by giving the <div class="fixeddiv"> a style="display: none". Then add the following (since you're already using jQuery):
$(document).ready(function () {
var contentOffset = getOffset();
function getOffset() {
var allOffsets = $("div#content").offset();
return allOffsets.top;
}
$(window).resize(function () {
contentOffset = getOffset();
});
$(window).scroll(function () {
var windowTop = $(window).scrollTop();
if (windowTop > contentOffset) {
$("div.fixeddiv").show();
} else {
$("div.fixeddiv").hide();
}
});
});
Here's what this code does. When the document is done loading, it gets the number of pixels that the "content" div is from the top of the document (offset). It does this again any time the window is resized. Then, when someone scrolls up or down, it gets the number of pixels that are already hidden above the scroll (scrollTop). If the number of hidden pixels is greater than the offset of the #content div from the top of the window, that means we've scrolled past the top of the content div and should show the icon. Otherwise, we should hide the icon.
I am very new to javascript.
I need a nav bar at the top to disappear and get replace by a smaller one at a certain scrolltop period. Once I reach a certain scroll top number I need the function to be executed and stay "faded-out" until you scroll back up to the same scroll top number.
I have been experimenting with this:
<script type="text/javascript">
$(window).scroll(function () {
if ($(document).scrollTop() > 250 ) {
$('#moving_nav').removeClass('tiny');
$('.subhead, .navbar-brand').fadeIn(0.1);
} else {
$('#moving_nav').addClass('tiny');
$('.subhead, .navbar-brand').fadeOut(0.1);
}
});
</script>
The problem I have right now its doing alot of funky things. At 250 it work ok, but is unable to do the reverse when scrolling up and when I change the number, at some point while scrolling down it goes back to its original state.
Please let me know how my code looks? Is there a more accurate/ correct way to go about this?
Thank you so much!
http://jsfiddle.net/NotJavascriptFriendly/F38As/
If you take a look at http://www.kahuna-webstudio.fr/ and scroll down the page about 50 pixels or so you will see a div on the left side of the screen slide out. I have managed to duplicate this effect but there is one thing that escapes me; and that is when you hit refresh on my page my jquery programming resets. I don't want this to happen. http://www.kahuna-webstudio.fr/ has it working perfectly. On their page when scroll down 50 pixels and the left nav appears and even when you hit refresh the left nav is still there. The left nav only disappears when the user scrolls back to the top of the page.
What is currently working: The user scrolls down 296 pixels on my page and the left nav slides out and the user brings the scroll bar back to the top of the page (pixels less than 25) and the left nav slides back and disappears. This is all working.
What is not working: But let's say the user scrolls down 296 pixels and the left nav slides out and then the user hits refresh while they are viewing the page. Well in this case the left nav disappears. My jquery programming is reset. I want the left nav, when the user is at 296 pixels or greater, to always be visible even if the user hits refresh.
My code is below. I hope my question makes sense and I welcome any help. Thank you.
$(window).scroll(function () {
var wintop = $(window).scrollTop();
var docheight = $(document).height();
var winheight = $(window).height();
var newwidthgrow = 80;
var smallheight = 0;
var smallwidth = 0;
//var expanded = "false";
if ((wintop > 296)) {
//expanded = "true";
$("#slidebottom").stop().animate({
height: docheight + "px"
}, 'fast', function () {
$("#slidebottom").stop().animate({
width: newwidthgrow + "px"
}, 'slow', function () {
$("#slidebottomContents").fadeIn();
});
});
}
if ((wintop < 25)) {
//expanded = "false";
$("#slidebottom").stop().animate({
height: docheight + "px"
}, 'fast', function () {
$("#slidebottomContents").fadeOut(function () {
$("#slidebottom").stop().animate({
width: smallwidth + "px"
});
});
});
}
});
If you don't have code in place to remember the scroll position before a refresh, the page will always refresh and scroll position will be 0 again. It sounds like that's not your desired functionality. Triggering a scroll at startup will not fix your problem unless you set the correct window scroll position before triggering it.
The example page you gave looks like it uses multiple scroll libraries, one of which (not sure which one) probably handles setting the scroll position on a refresh.
To do it yourself, you'd have to make use of local storage or the url like explained here:
Refresh Page and Keep Scroll Position
Have this window scroll function in a separate place. Call it from window scroll and also from document ready. This will make sure that the user's position is checked both when the page is being scrolled and when the page is loaded/refreshed.
You can use cookie to solve this probelm if you don't want to use server side to fix position when page is reloaded.
I want a solution either using a hashtag pointing at the name of an anchor tag or javascript.
The javascript I am currently using looks like this window.scroll(0, 20000);. The problem is that this causes the window jerk down when a user arrives on the page.
I know there are jQuery animations that make this movement more gradual. However, what I want is something that makes the movement of the window imperceptible to the user. I want to be as if the user landed at the bottom of the page.
The problem you face is that you wish to go to the bottom of your page which has not loaded yet. I would consider loading the page in a hidden format then show it when it has all loaded and after scrolling the user at the location you want. Use the focus or scroll to methods.
Take a look at the filament group website.
http://filamentgroup.com/
they hide the page with a loading screen until it is ready.
This way there is no jerk.
Hope this helps.
In loop it works, if the page is fully loaded and shown:
for(var n=0;n<1000;n++) window.scrollBy(0,20);
(Notice that 20*1000=20000, which was the original place to scroll.)
Teemu's answer doesn't seem to work for me (it goes straight to the bottom, making the loop with scrollBy stepping invisible), because it doesn't implement a delay.
If you mean to animate from top to bottom of the page in a 1000ms, try something more like this:
for (var n = 0; n < 1000; n += 1) {
setTimeout(function () {
window.scrollBy(0, document.height / 1000);
}, n);
}
That will give a 1 second (1000ms) animation, scrolling to the bottom in roughly 1000 steps.