jQuery scroll along x-axis: improve performance? - javascript

I have this bit of script here that takes some position:absolute elems and scrolls them along the x-axis only. It works but is super slow. Any way to speed up the performance?
(function() {
var $menu = $('.gallery-nav ul'),
$headA = $("header .home"),
leftOffset1 = parseInt($menu.css('left')),
leftOffset2 = parseInt($headA.css('left'));
$(window).scroll(function(){
$menu.css({
'left': $(this).scrollLeft() + leftOffset1
});
$headA.css({
'left': $(this).scrollLeft() + leftOffset2
});
});
})();
UPDATE: http://jsfiddle.net/davidpm/LeTEX/2/

I don't get your approach here since there is a perfect and very very speedy way only using CSS for that task.
You can simply set your element's position to fixed which means that they'll STAY AT THE POSITION regardless of document width/height or scrolling.
myElement{ position: fixed; left: 0; }
See DA new FIDDLE

Related

How to apply var height = $(window).height() - 20; to .followTo() function

I have this script. Its pretty simple. But my JS skills are shaky at best. It makes the navigation (which is positioned to the bottom of the window) scroll with the content until it reaches the top of the page then remains as fixed. Or as some would say "Sticky"
The issue im having is since my banner is 100% in height. The .followTo(830); only works on my screen resolution. How do I make followTo() find the windows current height and then follow to that height and then subtract 20px from the followTo value? That would be ideal. Can this be accomplished fairly simply?
var windw = this;
$.fn.followTo = function ( pos ) {
var $this = this,
$window = $(windw);
$window.scroll(function(e){
if ($window.scrollTop() > pos) {
$this.css({
position: 'fixed',
top: "20px"
});
} else {
$this.css({
position: 'absolute',
bottom: '0',
});
}
});
};
$('#mainNav').followTo(830);
Someone said I need to use var height = $(window).height() - 20; but I am not sure how to apply it and they refused to elaborate instead just downvoting my posts and refering me to the entire jquery API.. Which isnt my learning style.
Ive also attempted to use if ($(document).height() - $window.height() - $('#mainNav').scrollTop() < pos) I think im just messing up the syntax?
Just use the var height = $(window).height() - 20; in place of the 830 like this:
var height = $(window).height() - 20;
$('#mainNav').followTo(height);
Just keep in mind that the window size can change (for example the browser window gets resized or the device's orientation changes)

scrollTop suddenly not working for sticky menu

I had this working with no problems for the entire build of the site. Then, the day I was supposed to launch, the sticky menu stopped working right. The menu is supposed to start at the bottom, scroll to the top, then stick (position: fixed).
Now, it scrolls about 10px and then jumps to the top. Why is the scrollTop distance not calculating correctly?
Live site at [site no longer exists]
Here's the code for the sticky menu. I'm also using JS to set min-height of divs to window height, but haven't included that code here.
$(function(){
var stickyRibbonTop = $('#wrapper-wcf53badf7ebadf7').offset().top;
$(window).scroll(function(){
if( $(window).scrollTop() > stickyRibbonTop ) {
$('#wrapper-wcf53badf7ebadf7').css({position: 'fixed', top: '0px', 'background-image':'url(http://amarshall.360zen.com/wp-content/uploads/2014/07/menu-fade-background2.png)'});
$('#block-bcf53bf14093931c').css({display: 'block'});
} else {
$('#wrapper-wcf53badf7ebadf7').css({position: 'static', top: '0px','background-image':'none'});
$('#block-bcf53bf14093931c').css({display: 'none'});
}
});
});
Thanks in advance for any help! I'm not a JS or jQuery expert yet, so any suggestions for cleaning things up would be appreciated.
NOTE: The site is built on WordPress, so no-conflict mode is in effect.
I think you are initialising the sticky menu function before you set the min-height of $('big-div').
On page load, the menu starts at 54px from the top, and so when you store the offset().top value as stickyRibbonTop, it is stored at 54px. Then on your scroll event you are comparing against this.
Try setting the min-height of the divs first in your code, then run this same script afterwards. The value of stickyRibbonTop should then be correct.
Bear in mind that you will need to reset stickyRibbonTop every time the window.height() is updated, so you should probably make this sticky menu function a named function and call it at the end of the wrapper_height function. something like this:
function stickyNav() {
var stickyRibbonTop = $('#wrapper-wcf53badf7ebadf7').offset().top;
$(window).unbind('scroll', scrollEvent);
$(window).on('scroll', stickyRibbonTop, scrollEvent);
};
function scrollEvent(event) {
var stickyRibbonTop = event.data;
if ($(window).scrollTop() > stickyRibbonTop) {
$('#wrapper-wcf53badf7ebadf7').css({ position: 'fixed', top: '0px', 'background-image': 'url(http://www.adammarshalltherapy.com/wp-content/uploads/2014/07/menu-fade-background2.png)' });
$('#block-bcf53bf14093931c').css({ display: 'block' });
}
else {
$('#wrapper-wcf53badf7ebadf7').css({ position: 'static', top: '0px', 'background-image': 'none' });
$('#block-bcf53bf14093931c').css({ display: 'none' });
}
};
function wrapper_height() {
var height = $(window).height();
var wrapperheight = height - 75;
wrapperheight = parseInt(wrapperheight) + 'px';
$(".bigDiv").css('min-height', wrapperheight);
$("#wrapper-wcf53bad125d7d9a").css('height', wrapperheight);
stickyNav();
}
$(function () {
wrapper_height();
$(window).bind('resize', wrapper_height);
});

Get the position of the scrollbar using javascript

So I am trying to show a tooltip like box as I scroll my webpage and I would like it to follow the scrollbar along the right side of the page.
I looked around and found something to attempt to accomplish that as shown below:
function returnPercentHeight(){
var a = document.getElementById('rightPanel').scrollTop;
var b = document.getElementById('rightPanel').scrollHeight - document.getElementById('rightPanel').clientHeight;
return ((a/b) * 100);
}
I then append a % to the end and set the top margin of the tooltip to that returned value. This works pretty well (sort of) I have to adjust the return((a/b) * x) part (x) to make it follow the scrollbar based on the size of the browser window. Is there a better way to accomplish what I am trying to do? (NOTE: I can only use javascript, no JQuery please.)
EDIT:
Only the div given an ID of 'RightPanel' is scrolling, I am not using the scrollbar on the browser, but a scrollbar on an inner div.
There are three ways to do so:
First:
is to use the fixed position as following;
Position: Fixed;
Second:
With jQuery;
$(function(){
$(window).on('scroll', function() {
var scrollPOS = $(document).scrollTop();
$('.scroll').css({
top: scrollPOS
});
}).scroll();
});
Third:
Same as the previous, only animated;
$(window).on('scroll', function() {
$("#div").stop().animate({
"marginTop": ($(window).scrollTop()) + "px",
"marginLeft":($(window).scrollLeft()) + "px"}, "slow" );
});
Although IE doesn't support, this is the coolest I've seen:
// get
var x = window.scrollX,
y = window.scrollY;
// set
window.scrollTo(1, 2);

Make a navigation bar retain position when scrolled

I know this question has been asked before, but I'm pretty sure after checking them out, that none of the navigation bars where built like this one.
I'm basically having trouble making the navigation bar "seamlessly" switch to a fixed position at the top of the screen after scrolling past its original position, then back again.
I have included the code, and an example here: http://jsfiddle.net/r2a6U/
Here is the actual function which makes the div switch to fixed position mode:
var navPos = $('#navContainer').offset().top;
$(window).scroll(function(){
var fixIT = $(this).scrollTop() >= navPos;
var setPos = fixIT ? 'fixed' : 'relative' ;
var setTop = fixIT ? '0' : '600' ;
$('#navContainer').css({position: setPos});
$('#navContainer').css({'top': setTop});
});
Any help would be much appreciated.
Cheers
You can fix your issue to remove the styles instead of setting them to relative and 600px. I suggest you add/remove a class in JavaScript which will then apply the fixed CSS though. You will end up with much nicer and cleaner JavaScript.
Also make sure you center #navContainer properly when it's fixed.
jsFiddle
CSS
#navContainer.fixIT {
position:fixed;
top:0;
/* these will ensure it is centered so it doesn't jump to the side*/
left:0;
right:0;
text-align:center;
}
JS
var navPos = $('#navContainer').offset().top;
$(window).scroll(function(){
var fixIT = $(this).scrollTop() >= navPos;
if (fixIT)
$('#navContainer').addClass('fixIT');
else
$('#navContainer').removeClass('fixIT');
});
Fix it in here: jsFiddle
Only a small script update:
var navPos = $('#navContainer').offset().top;
$(window).scroll(function(){
var navContainer = $('#navContainer');
if( $(this).scrollTop() >= navPos ) {
// make it fixed to the top
$('#navContainer').css({ 'position': 'fixed', 'top': 0 });
} else {
// restore to orignal position
$('#navContainer').css({ 'position': 'relative', 'top': 600 });
}
});

JQuery div fall down effect onload

I'm trying to get a large logo (in the header of my site) to fall down into the header area on load. And so this is the only jquery function that I can find that seems to fit the idea.
http://jsfiddle.net/apHLu/279/
var $dropDiv = $('#dropDiv');
$('#holder a').on('click', function() {
// get position of the element we clicked on
var offset = $(this).offset();
// get width/height of click element
var h = $(this).outerHeight();
var w = $(this).outerWidth();
// get width/height of drop element
var dh = $dropDiv.outerHeight();
var dw = $dropDiv.outerWidth();
// determine middle position
var initLeft = offset.left + ((w/2) - (dw/2));
// animate drop
$dropDiv.css({
left: initLeft,
top: $(window).scrollTop() - dh,
opacity: 0,
display: 'block'
}).animate({
left: initLeft,
top: offset.top - dh,
opacity: 1
}, 300, 'easeOutBounce');
});
I basically want to know, is it possible to switch the click trigger to an onload call? I don't want to be muddling around trying to get it to work if it's not possible.
Thank you.
Here is an updated Fiddle. $(function() { ... }); is short for 'Document is ready'. I also wrapped the function in setTimeout();, because it was firing a little quick to see the full effect. Change the second parameter in setTimeout to adjust the time it waits to fire...
Updated (per #coby suggestion): If you do have a large amount of images you could change $(function() { to window.onload(function() {. Ready doesn't wait for all the images to be completely loaded.

Categories