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jQuery Transparent Menu on Scroll Up

What I am trying to achieve is something similar to this: http://www.thoughtspot.com/
I'm nearly there! What I can't replicate is how the navigation has a transparent background when scrolling up and then it disappears.
Could anyone assist me on this?
function hasScrolled() {
var st = $(this).scrollTop();
// Make sure they scroll more than delta
if(Math.abs(lastScrollTop - st) <= delta)
return;
// If they scrolled down and are past the navbar, add class .nav-up.
// This is necessary so you never see what is "behind" the navbar.
if (st > lastScrollTop && st > navbarHeight){
// Scroll Down
$('header').removeClass('nav-down').addClass('nav-up');
} else {
// Scroll Up
if(st + $(window).height() < $(document).height()) {
$('header').removeClass('nav-up').addClass('nav-down');
}
}
lastScrollTop = st;
}
For the full code please view the jsfiddle I have created:
http://jsfiddle.net/s6mLJ/2257/
Thanks everyone!

here you go just add opacity to the classes and css transition handles the rest:
opacity: 0
I have also added a linear transparent background, to make it similar to your example.
http://jsfiddle.net/s6mLJ/2262/
NEW VERSION
http://jsfiddle.net/s6mLJ/2313/

Adding a class to a div when the user has scrolled down an X amount of pixels

I'm using the code below to add/remove a class depending on which direction a user is scrolling. As of now, the class gets added as soon as the user scrolls down from point 0. I would like the class to get added when the user scrolls down at least an X amount of pixels. I tried changing the 0 in the lastScrollTop variable but it didn't work. Can someone help me out?
var lastScrollTop = 0;
$(window).scroll(function(event){
var st = $(this).scrollTop();
if (st > lastScrollTop){
$('#masthead').addClass('unpinned');
} else {
$('#masthead').removeClass('unpinned');
}
lastScrollTop = st;
});
Note: The code is set so that the class gets removed as soon as the user starts scrolling back up from any point. I would like to keep this aspect.

All you need to do is wrap that jQuery addClass call in an if statement checking the size of st like this:
if(st > 2000) $('#masthead').addClass('unpinned');
That will only add the class once the user has scrolled down 2000px.

This will work for you
var scrollLimit = 600;
var lastScrollTop;
$(window).scroll(function(event){
var st = $(this).scrollTop();
console.log(st,lastScrollTop);
if (st > scrollLimit){
$('#masthead').addClass('unpinned');
}
if(st < lastScrollTop){
$('#masthead').removeClass('unpinned');
}
lastScrollTop = st;
});
DEMO

Javascript DIV Movement on scroll

NIm creating an animation that moves a div incrementally on scroll. I'm close but I don't think my code is the most efficient and I don't know how to adapt it to add more arguments. So for instance, hitting a certain height on the page will then move the object right and stop moving it down. Below is my JS and the codepen can be found at;
http://codepen.io/anon/pen/KxHwu - Original
http://codepen.io/anon/pen/DLxqg - Messing about with moving right
var lastScrollTop = 0;
var boxPosition = $('#box').position();
var row2Position = $('#row2').position();
var distance = $('#row2').offset().top,
$window = $(window);
console.log(distance);
$window.scroll(function() {
if ( $window.scrollTop() >= distance - 400 ) {
var st = $(window).scrollTop();
console.log(st);
$('#box').css({top: 0 + st});
//CODE NOT WORKING
if(st >= 270) {
var boxPos = $('#box').position();
console.log(boxPos.left);
$('#box').css({left: boxPos.left + st});
}
//
lastScrollTop = st;
}
});
I'm looking for the box to start scrolling like it does, then when it hits half of row 2 scroll right.
I hope I have explained this in an easy way!
Thanks

http://codepen.io/anon/pen/tHwlq
Here is an example of how to do it; you'll need to tweak the numbers to make it work as you plan.
var $window = $(window);
var $box = $("#box");
$window.scroll(function() {
var scrollTop = $window.scrollTop();
if (scrollTop >= 250 && scrollTop < 400) {
$box.css({top: -250 + scrollTop});
} else if(scrollTop >= 400 && scrollTop < 600) {
$box.css({left: (50+(scrollTop-400)/2)+"%"})
}
});
If your project has numerous elements like this, I'd recommend the ScrollMagic (http://janpaepke.github.io/ScrollMagic/) library.
As far as efficiency is concerned I'd recommend the following:
1) Cache the jQuery selectors (note $box variable). Otherwise, jQuery will have to query the DOM on every scroll event.
2) Cache scrollTop rather then querying it multiple times within the event callback.
3) Although left and top work, using the transform: translate() property is more efficient, especially on mobile devices. (https://developer.mozilla.org/en-US/docs/Web/CSS/transform). However, on most mobile devices, scroll events only fire at the completion of a scroll, not while a page is scrolling.

jQuery double animation using the jquery easing plugin

I want to implement something like this page does: link
Look at the Clicker box. The box has two animations going on. One for the easeInQuad, then the other animation is for the easeInOutSine.
How can I implement something like that in my own function?
$(function()
{
var iH = window.innerHeight + 80;
var position = $(window).scrollTop();
$(window).scroll(function()
{
var scroll = $(window).scrollTop();
if(scroll > position)
{
$("body").animate(
{
scrollTop: iH
},1000,
"easeInOutQuart")
.animate(
{
scrollTop: parseInt($(window).scrollTop()) - 80
},1000,
"easeInOutQuart");
}
else if(scroll < position)
{
$("body").get(0).scrollTop = 0;
}
position = $(window).scrollTop();
});
});
The second animate doesn't work quite well. But it does scroll it up. But it scroll it up too much not just 80 pixels. It scroll it up to the top, then the animation gets into an infinite loop. After the second .animate it will continue to animate it again and again and again. Non stop.

I think its better to use a toggle effect
http://www.sohtanaka.com/web-design/examples/toggle/

$("body").stop(true)
This will clear all animation Queues on the object.
http://docs.jquery.com/Effects/stop

Fading Element on Scroll

I'm curious how I can create a DIV (or anything really) that I can fade (or change opacity of) when a user scrolls down the page. This DIV would sit at the top of the page, but only be clearly visible when at the very top of the page.
Additionally, it would be ideal if I I could have this element fade back in onmouseover, regardless of the current scrolled position on the page.

jQuery would allow for a succinct solution, whilst hiding most browser discrepancies. Here's a quick mock-up to get you started:
<script type="text/javascript">
//when the DOM has loaded
$(document).ready(function() {
//attach some code to the scroll event of the window object
//or whatever element(s) see http://docs.jquery.com/Selectors
$(window).scroll(function () {
var height = $('body').height();
var scrollTop = $('body').scrollTop();
var opacity = 1;
// do some math here, by placing some condition or formula
if(scrollTop > 400) {
opacity = 0.5;
}
//set the opacity of div id="someDivId"
$('#someDivId').css('opacity', opacity);
});
});
</script>
See also:
jQuery
Selectors
CSS
Events/Scroll
CSS/ScrollTop
CSS/ScrollLeft

I thought I would give it a go using the actual value of scrollTop to dictate the opacity level, thus getting a smooth fade. I also added the hover state for the second part. Thanks to David for refining the maths for me.
//reduce the opacity of the banner if the page is scrolled.
$(window).scroll(function () {
var height = $("body").height();
var scrollTop = $("body").scrollTop();
var opacity = 1;
if(scrollTop < 41)
{opacity = 1-Math.floor(scrollTop)/100;}
else
{opacity = 0.6;}
$("#header").css("opacity", opacity);
$("#header").hover(function(){
$(this).css("opacity", 1);
},function(){
$(this).css("opacity", 0.6);
});
});

Use scroll event, and analyse value of document.documentElement.scrollTop to set appropriated opacity.
http://www.quirksmode.org/dom/events/scroll.html