При копировании этого кода отсюда: https://codepen.io/nenadkaevik/pen/odyrGm?editors=1111
И связать его с моими CSS и JavaScript, сохраненными в том же файле, похоже, не работает, все работает, кроме кнопок и анимации при нажатии.
var tabs = $('.tabs');
var items = $('.tabs').find('a').length;
var selector = $(".tabs").find(".selector");
var activeItem = tabs.find('.active');
var activeWidth = activeItem.innerWidth();
$(".selector").css({
"left": activeItem.position.left + "px",
"width": activeWidth + "px"
});
$(".tabs").on("click", "a", function(e) {
e.preventDefault();
$('.tabs a').removeClass("active");
$(this).addClass('active');
var activeWidth = $(this).innerWidth();
var itemPos = $(this).position();
$(".selector").css({
"left": itemPos.left + "px",
"width": activeWidth + "px"
});
});@import url('https://fonts.googleapis.com/css?family=Roboto');
body {
font-family: 'Roboto', sans-serif;
}
h2 {
margin: 0px;
text-transform: uppercase;
}
h6 {
margin: 0px;
color: #777;
}
.wrapper {
text-align: center;
margin: 50px auto;
}
.tabs {
margin-top: 50px;
font-size: 15px;
padding: 0px;
list-style: none;
background: #fff;
box-shadow: 0px 5px 20px rgba(0, 0, 0, 0.1);
display: inline-block;
border-radius: 50px;
position: relative;
}
.tabs a {
text-decoration: none;
color: #777;
text-transform: uppercase;
padding: 10px 20px;
display: inline-block;
position: relative;
z-index: 1;
transition-duration: 0.6s;
}
.tabs a.active {
color: #fff;
}
.tabs a i {
margin-right: 5px;
}
.tabs .selector {
height: 100%;
display: inline-block;
position: absolute;
left: 0px;
top: 0px;
z-index: 1;
border-radius: 50px;
transition-duration: 0.6s;
transition-timing-function: cubic-bezier(0.68, -0.55, 0.265, 1.55);
background: #05abe0;
background: -moz-linear-gradient(45deg, #05abe0 0%, #8200f4 100%);
background: -webkit-linear-gradient(45deg, #05abe0 0%, #8200f4 100%);
background: linear-gradient(45deg, #05abe0 0%, #8200f4 100%);
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#05abe0', endColorstr='#8200f4', GradientType=1);
}<script src = "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class = "wrapper">
<h2>Elastic Tabs</h2>
<h6>Click on tabs to see them in action</h6>
<nav class = "tabs">
<div class = "selector"></div>
<a href = "#" class = "active"><i class = "fas fa-burn"></i>Avengers</a>
<a href = "#"><i class = "fas fa-bomb"></i>Guardians of The Galaxy</a>
<a href = "#"><i class = "fas fa-bolt"></i>Thor</a>
<a href = "#"><i class = "fab fa-superpowers"></i>Black Panther</a>
</nav>
</div>Вам нужно включить файлы JavaScript и CSS, которые находятся в настройках, в данном случае jquery и fontawesome.



![Безумие обратных вызовов в javascript [JS]](https://i.imgur.com/WsjO6zJb.png)


Вы забыли добавить библиотеку jquery?
Давайте попробуем этот html
<!DOCTYPE html>
<html lang = "en"
class = "">
<head>
<meta http-equiv = "Content-Type"
content = "text/html; charset=UTF-8">
<script src = "./index_files/console_runner-1df7d3399bdc1f40995a35209755dcfd8c7547da127f6469fd81e5fba982f6af.js.download"></script>
<script src = "./index_files/css_reload-5619dc0905a68b2e6298901de54f73cefe4e079f65a75406858d92924b4938bf.js.download"></script>
<meta name = "robots"
content = "noindex">
<link rel = "shortcut icon"
type = "image/x-icon"
href = "https://static.codepen.io/assets/favicon/favicon-8ea04875e70c4b0bb41da869e81236e54394d63638a1ef12fa558a4a835f1164.ico">
<link rel = "mask-icon"
type = ""
href = "https://static.codepen.io/assets/favicon/logo-pin-f2d2b6d2c61838f7e76325261b7195c27224080bc099486ddd6dccb469b8e8e6.svg"
color = "#111">
<link rel = "canonical"
href = "https://codepen.io/nenadkaevik/pen/odyrGm?editors=1111">
<link rel = "stylesheet"
href = "./index_files/all.css">
<style class = "cp-pen-styles">
@import url('https://fonts.googleapis.com/css?family=Roboto');
body {
font-family: 'Roboto', sans-serif;
}
h2 {
margin: 0px;
text-transform: uppercase;
}
h6 {
margin: 0px;
color: #777;
}
.wrapper {
text-align: center;
margin: 50px auto;
}
.tabs {
margin-top: 50px;
font-size: 15px;
padding: 0px;
list-style: none;
background: #fff;
box-shadow: 0px 5px 20px rgba(0, 0, 0, 0.1);
display: inline-block;
border-radius: 50px;
position: relative;
}
.tabs a {
text-decoration: none;
color: #777;
text-transform: uppercase;
padding: 10px 20px;
display: inline-block;
position: relative;
z-index: 1;
transition-duration: 0.6s;
}
.tabs a.active {
color: #fff;
}
.tabs a i {
margin-right: 5px;
}
.tabs .selector {
height: 100%;
display: inline-block;
position: absolute;
left: 0px;
top: 0px;
z-index: 1;
border-radius: 50px;
transition-duration: 0.6s;
transition-timing-function: cubic-bezier(0.68, -0.55, 0.265, 1.55);
background: #05abe0;
background: -moz-linear-gradient(45deg, #05abe0 0%, #8200f4 100%);
background: -webkit-linear-gradient(45deg, #05abe0 0%, #8200f4 100%);
background: linear-gradient(45deg, #05abe0 0%, #8200f4 100%);
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#05abe0', endColorstr='#8200f4', GradientType=1);
}
</style>
</head>
<body>
<div class = "wrapper">
<h2>Elastic Tabs</h2>
<h6>Click on tabs to see them in action</h6>
<nav class = "tabs">
<div class = "selector"
style = "width: 138.5px;"></div>
<a href = "https://www.google.com/_/chrome/newtab?rlz=1C1CHBF_deDE787DE787&ie=UTF-8#"
class = "active"><i class = "fas fa-burn"></i>Avengers</a>
<a href = "https://www.google.com/_/chrome/newtab?rlz=1C1CHBF_deDE787DE787&ie=UTF-8#"><i class = "fas fa-bomb"></i>Guardians of The Galaxy</a>
<a href = "https://www.google.com/_/chrome/newtab?rlz=1C1CHBF_deDE787DE787&ie=UTF-8#"><i class = "fas fa-bolt"></i>Thor</a>
<a href = "https://www.google.com/_/chrome/newtab?rlz=1C1CHBF_deDE787DE787&ie=UTF-8#"><i class = "fab fa-superpowers"></i>Black Panther</a>
</nav>
</div>
<script src = "./index_files/stopExecutionOnTimeout-de7e2ef6bfefd24b79a3f68b414b87b8db5b08439cac3f1012092b2290c719cd.js.download"></script>
<script src = "./index_files/jquery.min.js.download"></script>
<script>var tabs = $('.tabs');
var items = $('.tabs').find('a').length;
var selector = $(".tabs").find(".selector");
var activeItem = tabs.find('.active');
var activeWidth = activeItem.innerWidth();
$(".selector").css({
"left": activeItem.position.left + "px",
"width": activeWidth + "px"
});
$(".tabs").on("click", "a", function(e) {
e.preventDefault();
$('.tabs a').removeClass("active");
$(this).addClass('active');
var activeWidth = $(this).innerWidth();
var itemPos = $(this).position();
$(".selector").css({
"left": itemPos.left + "px",
"width": activeWidth + "px"
});
});
</script>
</body>
</html>
Пожалуйста, добавьте минимальный воспроизводимый пример