Develop Reference

Making animations in react without using Jquery

I am trying to create a on scroll fade animation in my website i am using reactjs for this although i didnt knew how to bring this effect so i found this jquery code to achive this effect but i want to bring this effect without jquery using plane react is it possible? here is the jquery code:
var html = $('html');
// Detections
if (!("ontouchstart" in window)) {
html.addClass("noTouch");
}
if ("ontouchstart" in window) {
html.addClass("isTouch");
}
if ("ontouchstart" in window) {
html.addClass("isTouch");
}
if (document.documentMode || /Edge/.test(navigator.userAgent)) {
if (navigator.appVersion.indexOf("Trident") === -1) {
html.addClass("isEDGE");
} else {
html.addClass("isIE isIE11");
}
}
if (navigator.appVersion.indexOf("MSIE") !== -1) {
html.addClass("isIE");
}
if (
navigator.userAgent.indexOf("Safari") != -1 &&
navigator.userAgent.indexOf("Chrome") == -1
) {
html.addClass("isSafari");
}
// On Screen
$.fn.isOnScreen = function() {
var elementTop = $(this).offset().top,
elementBottom = elementTop + $(this).outerHeight(),
viewportTop = $(window).scrollTop(),
viewportBottom = viewportTop + $(window).height();
return elementBottom > viewportTop && elementTop < viewportBottom;
};
function detection() {
for (var i = 0; i < items.length; i++) {
var el = $(items[i]);
if (el.isOnScreen()) {
el.addClass("in-view");
} else {
el.removeClass("in-view");
}
}
}
var items = document.querySelectorAll(
"*[data-animate-in], *[data-detect-viewport]"
),
waiting = false,
w = $(window);
w.on("resize scroll", function() {
if (waiting) {
return;
}
waiting = true;
detection();
setTimeout(function() {
waiting = false;
}, 100);
});
$(document).ready(function() {
setTimeout(function() {
detection();
}, 500);
for (var i = 0; i < items.length; i++) {
var d = 0,
el = $(items[i]);
if (items[i].getAttribute("data-animate-in-delay")) {
d = items[i].getAttribute("data-animate-in-delay") / 1000 + "s";
} else {
d = 0;
}
el.css("transition-delay", d);
}
});
});
is there any way that i can bring this effect from react only or do i have to use :
import $ from jquery
thanks in advance

Change JS scrolling event to time interval

I have an image gallery I'm using for a webpage. Currently, the gallery images change when the user scrolls, but I'd like to change it so that the images change on a time interval, and are on a loop instead of an up scroll to go back and a down scroll to go forward. I'm pretty new to Javascript, so I'm now sure how to change the below script from scrolling to timed.
<script>
$(document).ready(function() {
var curPage = 1;
var numOfPages = $(".skw-page").length;
var animTime = 1000;
var scrolling = false;
var pgPrefix = ".skw-page-";
function pagination() {
scrolling = true;
$(pgPrefix + curPage).removeClass("inactive").addClass("active");
$(pgPrefix + (curPage - 1)).addClass("inactive");
$(pgPrefix + (curPage + 1)).removeClass("active");
setTimeout(function() {
scrolling = false;
}, animTime);
};
function navigateUp() {
if (curPage === 1) return;
curPage--;
pagination();
};
function navigateDown() {
if (curPage === numOfPages) return;
curPage++;
pagination();
};
$(document).on("mousewheel DOMMouseScroll", function(e) {
if (scrolling) return;
if (e.originalEvent.wheelDelta > 0 || e.originalEvent.detail < 0) {
navigateUp();
} else {
navigateDown();
}
});
$(document).on("keydown", function(e) {
if (scrolling) return;
if (e.which === 38) {
navigateUp();
} else if (e.which === 40) {
navigateDown();
}
});
});
</script>

Just call setInterval, change what happens when navigateDown is called once all pages have been cycled through, and remove the scroll/keydown listeners.
$(document).ready(function() {
var curPage = 1;
var numOfPages = $(".skw-page").length;
var animTime = 1000;
var scrolling = false;
var pgPrefix = ".skw-page-";
function pagination() {
scrolling = true;
$(pgPrefix + curPage)
.removeClass("inactive")
.addClass("active");
$(pgPrefix + (curPage - 1)).addClass("inactive");
$(pgPrefix + (curPage + 1)).removeClass("active");
if (curPage === 1) $(pgPrefix + numOfPages).addClass("inactive");
setTimeout(function() {
scrolling = false;
}, animTime);
}
function navigateDown() {
if (curPage === numOfPages) curPage = 0;
curPage++;
console.log(curPage);
pagination();
}
setInterval(navigateDown, 5000); // 5000 ms == 5 s
});
.active {
color: purple;
}
.inactive {
display: none;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div>
<p class="skw-page skw-page-1 active">Page 1</p>
<p class="skw-page skw-page-2 inactive">Page 2</p>
<p class="skw-page skw-page-3 inactive">Page 3</p>
<p class="skw-page skw-page-4 inactive">Page 4</p>
</div>

You can use setInterval, also inside setInterval you should not call both the navigateUp and navigateDown functions, since this will nullify their pagination changes as defined in your code.
Also, since in your original code, the trigger to fire either of navigateDown and nvaigateUp functions depends on event passed from keydown and DOMmouseScroll, you will need to tweak my example code to fit your html. I can not give a complete example since your html part is missing here.
$(document).ready(function() {
var curPage = 1;
var numOfPages = $(".skw-page").length;
var animTime = 1000;
var scrolling = false;
var pgPrefix = ".skw-page-";
function pagination() {
scrolling = true;
$(pgPrefix + curPage).removeClass("inactive").addClass("active");
$(pgPrefix + (curPage - 1)).addClass("inactive");
$(pgPrefix + (curPage + 1)).removeClass("active");
setTimeout(function() {
scrolling = false;
}, animTime);
}
function navigateUp() {
if (curPage === 1) return;
curPage--;
pagination();
}
function navigateDown() {
if (curPage === numOfPages) return;
curPage++;
pagination();
}
setInterval(function() {
navigateUp();
/*
or call
navigateDown();
*/
}, animTime);
});

What is the problem in here? it is not working in chrome

Window.onscroll = () => {
if (Window.innerHeight + Window.scrolly >= document.body.offsetHeight) {
document.querySelector('body').style.background = 'green';
} else {
document.querySelector('body').style.background = 'white';
}
}
I am new at coding, learning from an online course. Now I am stuck at it. i don't know what is wrong in here

As was mentioned in the comment you got wrong letter cases: window, scrollY
const body = document.querySelector('body');
body.style.height = '200vh'; // without content there's no scroll, so this will produce scroll;
window.onscroll = () => {
if (window.innerHeight + window.scrollY >= document.body.offsetHeight) {
body.style.background = 'green';
} else {
body.style.background = 'white';
}
}

Execute javascript for certain screen size

I have a javascript function that I need modified for certain screen sizes, though I've tried "if (screen.width <= 960) {... " and "if (window.width <= 960) {..." , only the part after "else" get's executed, like it's not even looking at the screen width I'm placing in the parenthesis.
Here is my function ( I know it's poorly written, but I'm new to javascript):
$(document).ready(function(){
var numberofscroll = 0;
var lastScrollTop = 0;
$("#home").scroll(function(){
var st = $(this).scrollTop();
(st > lastScrollTop) ? numberofscroll++ : numberofscroll--;
console.log(numberofscroll);
console.log(lastScrollTop);
console.log(st);
if (numberofscroll<2){
change_background2(numberofscroll);
}
else if (numberofscroll<3){
change_background3(numberofscroll);
}
else if (numberofscroll<4){
change_background4(numberofscroll);
}
lastScrollTop = st;
});
function change_background2(numberofscroll){
var i;
for (i = 2) {
$("#home").css("background-position","0 -652px");
}
}
function change_background3(numberofscroll){
var i;
for (i = 3) {
$("#home").css("background-position","0 -1326px");
}
}
function change_background4(numberofscroll){
var i;
for (i = 4) {
$("#home").css("background-position","0 -1978px");
}
}
)};

Corrections:
Changed all the for to ifs.
Corrected the parentheses.
Assigned a temp variable to ternary operation.
Changed all the i to numberofscroll
I believe the corrected JavaScript is:
$(document).ready(function () {
var numberofscroll = 0;
var lastScrollTop = 0;
$("#home").scroll(function () {
var st = $(this).scrollTop();
n = (st > lastScrollTop) ? numberofscroll++ : numberofscroll--;
console.log(numberofscroll);
console.log(lastScrollTop);
console.log(st);
if (numberofscroll < 2) {
change_background2(numberofscroll);
} else if (numberofscroll < 3) {
change_background3(numberofscroll);
} else if (numberofscroll < 4) {
change_background4(numberofscroll);
}
lastScrollTop = st;
});
function change_background2(numberofscroll) {
if (numberofscroll == 2) {
$("#home").css("background-position","0 -652px");
}
}
function change_background3(numberofscroll) {
if (numberofscroll == 3) {
$("#home").css("background-position","0 -1326px");
}
}
function change_background4(numberofscroll) {
if (numberofscroll == 4) {
$("#home").css("background-position","0 -1978px");
}
}
});

I think you want to use the innerWidth property of window. (https://developer.mozilla.org/en/docs/Web/API/window/innerWidth).

jQuery load and append issue

im getting a little issue here. I have a wordpress theme that i need to add an infinite scroll effect. Ok, its working, but it doesnt look work properly. I set the current page and the number of pages, but it keeps adding the second page every time i reach the bottom.
What im doing wrong?
Ps.: I have tried the inifite-scroll plugin for wordpress, and it dont works with my template. Thanks!
$(function() {
var currentPage = 1;
var numPages = Math.ceil(pages / 4);
var browserName = "";
var ua = navigator.userAgent.toLowerCase();
if (ua.indexOf("opera") != -1) {
browserName = "opera";
} else if (ua.indexOf("msie") != -1) {
browserName = "msie";
} else if (ua.indexOf("safari") != -1) {
browserName = "safari";
} else if (ua.indexOf("mozilla") != -1) {
if (ua.indexOf("firefox") != -1) {
browserName = "firefox";
} else {
browserName = "mozilla";
}
}
$(window).scroll(function() {
if (browserName != "safari") {
var curScrollPos = $('html').scrollTop();
}
else {
var curScrollPos = $('body').scrollTop();
}
if (curScrollPos > 218) {
$("#sidebar").addClass("open");
}
if (curScrollPos < 218) {
$("#sidebar").removeClass("open");
}
var scrollBottom = $(document).height() - $(window).height() - $(window).scrollTop();
if (scrollBottom == 0) {
if (currentPage < numPages) {
$("<div>").load("page/" + (currentPage + 1), function() {
var newPosts = $(this).find("#content").html();
$("#content").append(newPosts);
});
currentPage++;
}
else {
}
}
});
// Infinite Scroll
});​

Possibly try this:
$("<div>").load("page/"+(currentPage+1), function() {
var newPosts = $(this).find("#content").html();
$("#content").append(newPosts);
currentPage++;
});
And remove the currentPage++;