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Issues with $(window).width() and scrolling

I am trying to get this code to only work if the device window is bigger than 960px, and it should only trigger when the window scrolls down 700px. The later part works however the first part does not.
The code works perfectly on where it fades in and then fades out, however I do not want it to do so on mobile devices, because the scroll point (700px) is too far down and is creating issues.
$(function () {
var header = $('.fadein');
$(window).scroll(function () {
var scroll = $(window).scrollTop();
if (($(window).width() < 960) && (scroll >= 700)) {
header.removeClass('.fadein').addClass('.fadeout').fadeIn();
} else {
header.removeClass('.fadeout').fadeOut().addClass('.fadein');
}
});
});

I think your main issue is accidentally using < 960 instead of > 960, but you might also change to checking innerWidth rather than width if you really are interested in the window's width and not just the screen's width.
For this demo I reduced the target values to 500 and 200 to work better in a SO snippet. (Resize your browser window and run the snippet again to see it working above and below the 500px threshold.)
console.log("width: " + $(window).innerWidth() );
$(window).scroll(function () {
const
div = document.getElementById("div"),
scroll = $(window).scrollTop();
if ( ($(window).innerWidth() > 500) && (scroll >= 200) ) {
div.style.backgroundColor = "yellow";
}
else {
div.style.backgroundColor = "white";
}
});
#div{ height: 300vh; border: 1px solid grey; }
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="div"></div>

Did you try to split that if statement ?
For example (second if will fire only if width is at least 960px)
if($(window).width() >= 960) {
if (scroll >= 700) {
header.removeClass('.fadein').addClass('.fadeout').fadeIn();
} else {
header.removeClass('.fadeout').fadeOut().addClass('.fadein');
}
}

Jquery add CSS class after 'X' amount of viewport height scrolled

So I have this jQuery function that adds / removes a CSS class to an element after 600px of the viewport height has been scrolled.
$(window).scroll(function() {
var scroll = $(window).scrollTop();
if (scroll >= 600) {
$(".cta_box").addClass('fadeout');
} else {
$(".cta_box").removeClass('fadeout');
}
});
I'd like to tweak it so instead of working based off a pixel value, it works off of the view height css measurement "VH", but the equivalent results are what matter in this case.

It can be done by getting the window height using $(window).height().
For instance suppose you have to scroll half the screen more (height is 150vh) and you have to detect when 40% has been scrolled:
$(window).scroll(function() {
var scroll = $(window).scrollTop();
if (scroll >= 0.4 * $(window).height()) {
$(".cta_box").addClass('fadeout');
} else {
$(".cta_box").removeClass('fadeout');
}
});
body{
margin: 0;
height: 150vh;
}
.cta_box {
height: 100%;
background: green;
}
.cta_box.fadeout {
background: grey;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="cta_box"></div>

Use a percentage of the window height to compare
$(window).scroll(function() {
var height = $(window).height(),
scroll = $(window).scrollTop()
limit = 0.6; //implies 60 vh or 60% of viewport height
if (scroll >= height*limit) {
$(".clearHeader").addClass("darkHeader");
} else {
$(".clearHeader").removeClass("darkHeader");
}
});
and even better would be to update some variable only when the window is resized to avoid computations all the time
var limit = 0.6, //implies 60 vh or 60% of viewport height
scrollLimit = 0;
$(window).resize(function(){
scrollLimit = $(window).height() * limit;
}).scroll(function() {
var scroll = $(window).scrollTop();
if (scroll >= scrollLimit ) {
$(".clearHeader").addClass("darkHeader");
} else {
$(".clearHeader").removeClass("darkHeader");
}
}).trigger('resize').trigger('scroll'); // trigger both events on start to force initial setup

Try something like this
$(window).scroll(function() {
var scroll = $(window).scrollTop();
if (scroll >= 500) {
$(".clearHeader").addClass("darkHeader");
} else {
$(".clearHeader").removeClass("darkHeader");
}
});

For retrieveing the viewport Height, you could use $(window).innerHeight():
$(window).scroll(function() {
var scroll = $(window).innerHeight();
if (scroll >= 600) {
$(".cta_box").addClass('fadeout');
} else {
$(".cta_box").removeClass('fadeout');
}
});
Hope this helps.
Leo.

Media queries and height & width defined in variable

I found this plugin online:
https://github.com/frenski/quizy-memorygame
As you can guess, it's a memory game in which you can choose the images to display on the cards. And it's great. But the thing is I'm trying to use media queries to make it more responsive, and it worked great until I realized that the width and height of the cards are defined not only in the CSS but also in a variable.
var quizyParams = {itemWidth: 156, itemHeight: 156, itemsMargin:40, colCount:3, animType:'flip' , flipAnim:'tb', animSpeed:250, resultIcons:true, randomised:true };
$('#tutorial-memorygame').quizyMemoryGame(quizyParams);
$('#restart').click(function(){
$('#tutorial-memorygame').quizyMemoryGame('restart');
return false;
});
How can I change the itemWidth and itemHeight depending on the size of the screen? Is that even possible?
I tried using a function like:
if(screen.width <= 480){
//change width and height to this
}else if (screen.width <= 780){
//change width and height to that
}else (screen.width <= 960){
//change width and height to this
}
But it didn't work...
All ideas are welcome! And thank you for your help.

Using if (screen.width <= 480) might not work onload, try use window.matchMedia() to match your CSS media queries:
if (window.matchMedia('(max-width: 480px)').matches) {
//...
} else {
//...
}

try this hope helpful you ....
$(document).ready(function() {
function checkWidth() {
var windowSize = $(window).width();
if (windowSize <= 479) {
console.log("screen width is less than 480");
}
else if (windowSize <= 719) {
console.log("screen width is less than 720 but greater than or equal to 480");
}
else if (windowSize <= 959) {
console.log("screen width is less than 960 but greater than or equal to 720");
}
else if (windowSize >= 960) {
console.log("screen width is greater than or equal to 960");
}
}
// Execute on load
checkWidth();
// Bind event listener
$(window).resize(checkWidth);
});​

$(window).on('scroll', function () when scroll to 50 %, i want to load few data

i want to load few data asap browser scrollbar travelling to 50 %
for what using jquery i wrote following funcation :
$(window).on('scroll', function () {
alert("scrolling");
if ($(window).scrollTop() + $(window).innerHeight() >= $(window)[0].scrollHeight * 0.5) {
if (counter < modules.length) {
LoadData(modules[counter]);
}
counter += 1;
}
})
but it is not working, how can i fixed that?
anthor try i made it is :
$(window).scroll(function () {
if ($(window).scrollTop() == $(document).height() - $(window).height()) {
alert("you are at bottom");
}
});
but i dont want alert fired at bottom, just at 50%

To detect that scrolling has reached 50% of your page use:
if ($(window).scrollTop() >= ($(document).height() - $(window).height())*0.5){
For the rest we should know what's inside LoadData(modules[counter]);
http://jsfiddle.net/carlodurso/a5wmLzfm/

Show div after scrolling 100px from the top of the page

I found this, but this does it 100px before the bottom of the page. I need it 100px from the top of the page. I know how to implement it, I've done other jquery animations, just not what needs to be in this one.
$(window).scroll(function(){
if($(window).scrollTop() + 100 > $(document).height() - $(window).height() ){
alert("at bottom");
}
});
And also, I need to know how to reverse this so the div disappears when the user scroll back up before the 100px.
This will be used for a navigation bar.
Edit2> This worked also:
$(window).scroll(function(){
if($(window).scrollTop() > 100){
$("#div").fadeIn("slow");
}
});
$(window).scroll(function(){
if($(window).scrollTop() < 100){
$("#div").fadeOut("fast");
}
});

Try this:
$(window).scroll(function() {
if ($(window).scrollTop() > 100) {
// > 100px from top - show div
}
else {
// <= 100px from top - hide div
}
});

Try this:
var menu = $("nav");
$(window).scroll(function(){
//more then or equals to
if($(window).scrollTop() >= 100 ){
menu.show();
//less then 100px from top
} else {
menu.hide();
}
});

I would recommend to do this:
$("#divname").hide();
$(window).scroll(function() {
if ($(window).scrollTop() > 100) {
$("#divname").fadeIn("slow");
}
else {
$("#divname").fadeOut("fast");
}
});
Now the div is already hidden when you visit your page.
Without this:
$("#divname").hide()
It would show and then perform a FadeOut. And that is not what you want.