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- Theory
- Theory
- Comments
Creating a like counter
Meow! I want to know how many people liked the news story. Make a counter!
There is no limit to perfection and things that the boss wants! We still have to finish the like system. Now the user can add and cancel their likes by clicking on the “heart” under the picture in the news story. But this does not take into account of how many people actually liked the news story so does not show the number. You can fix this by adding a counter.
The “heart” button is stored in the heart variable. When the user adds a like, the added class is added to the button and the “heart” becomes completely filled with color. When the like is canceled, the added class is cleared, and the button returns to its original state. The classList.toggle method is responsible for switching the class. We encountered this method in the introductory chapter. To display the number of likes on the page, the web designer prepared an element with the likes-number class.
This is what the button looks like in the markup:
<!-- No like, empty heart -->
<button class="heart"><span class="likes-number"></span></button>
<!-- Like has been added, heart filled with color -->
<button class="heart added"><span class="likes-number"></span></button>To save the number of likes, we need a counter variable. Its value will be a number.
// Assign a value (a number) to the variable
let number = 7;Please note that we do not place numbers in quotation marks.
Let’s call the counter variable counter and assign it the value 0. So long as no one clicks, there will be no likes. After that, output the value of the counter to the page using the textContent element property with the likes-number class. In the introductory chapter we already worked with the text content of elements.
Files
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<link rel="stylesheet" href="setting.css">
<link rel="stylesheet" href="style.css">
<title>FlashNews!</title>
</head>
<body class="page light-theme">
<header class="page-header">
<div class="container">
<span class="header-logo">
<img src="img/main-logo.svg" width="67" height="29" alt="FlashNews! portal logo">
</span>
<button class="theme-button" type="button">Change the theme</button>
</div>
</header>
<main class="inner-news">
<div class="container">
<h1 class="inner-heading">🔥 What shocking news! It’s so scandalous! Such a sensation!</h1>
<article class="news-full">
<img src="img/news-robot2.jpg" alt="A robot vacationing at a resort">
<div class="news-stats">
<button class="heart"><span class="likes-number"></span></button>
<time datetime="2019-12-22">22 December 2019</time>
</div>
<p>It turns out that you don’t have to be a cat to start programming in JavaScript! Scientists have created the first robot that can write and change its own code. He immediately learned how to code websites, and he left to work as a freelancer on Bali.</p>
</article>
</div>
</main>
<footer class="page-footer">
<div class="container">
<p>© FlashNews!</p>
<span class="footer-logo">
<img src="img/white-logo.svg" alt="FlashNews! portal logo">
</span>
</div>
</footer>
<script src="themes.js"></script>
<script src="likes.js"></script>
</body>
</html>
/* News story page styles */
.comment-form {
display: flex;
margin-bottom: 30px;
padding: 20px 12px;
}
.comment-inner {
position: relative;
flex-grow: 1;
margin-right: 10px;
}
.comment-label {
position: absolute;
top: -16px;
left: -9px;
padding: 4px 8px;
font-size: 10px;
line-height: 14px;
}
.comment-field {
width: 100%;
height: 30px;
padding: 0 10px;
border: none;
background-color: transparent;
font: inherit;
font-size: 14px;
line-height: 30px;
}
.comment-field::placeholder {
color: #aaaaaa;
font: inherit;
font-size: 14px;
font-style: italic;
}
.comment-field:focus::placeholder {
font-size: 0;
}
.comment-field:hover::placeholder,
.comment-field:active::placeholder {
opacity: 0.5;
}
.inner-news .inner-heading {
margin-bottom: 20px;
}
.news-full {
display: flex;
flex-direction: column;
margin-bottom: 24px;
}
.news-full img {
margin-bottom: 4px;
width: 100%;
height: 220px;
object-fit: cover;
}
.news-full .news-stats {
display: flex;
justify-content: space-between;
}
.news-full .heart {
padding: 12px 10px;
min-width: 40px;
min-height: 34px;
font-family: inherit;
font-weight: bold;
font-size: 16px;
border: none;
background-color: transparent;
background-repeat: no-repeat;
background-position: 12px;
cursor: pointer;
}
.heart .likes-number {
margin-left: 24px;
line-height: 14px;
}
.news-full time {
margin-top: 14px;
margin-right: 12px;
margin-bottom: 8px;
margin-left: 0;
}
.news-full p {
margin-top: 0;
margin-right: 12px;
margin-bottom: 16px;
margin-left: 12px;
font-size: 14px;
line-height: 24px;
}
.comment-feed h2 {
margin-top: 0;
margin-bottom: 12px;
}
.comment-list {
margin-top: 0;
margin-right: 0;
margin-bottom: 12px;
margin-left: 0;
padding: 0;
list-style: none;
counter-reset: comments;
}
.comment-list li {
margin-bottom: 6px;
padding: 10px 12px;
min-height: 36px;
font-size: 14px;
line-height: 24px;
}
.comment-list .user-comment {
position: relative;
display: flex;
}
.comment-list .user-comment::before {
counter-increment: comments;
content: "#" counter(comments);
padding-right: 12px;
margin-right: 12px;
border-right: 1px solid;
font-weight: bold;
}
.comment-list .user-comment::after {
position: absolute;
content: "";
width: 0;
height: 0;
bottom: 0;
left: -8px;
border: 4px solid;
border-left-color: transparent;
border-top-color: transparent;
}
@keyframes comment-blink-light {
0% {
background-color: #b6aaff;
opacity: 0;
}
20% {
opacity: 0.8;
}
}
@keyframes comment-blink-light-after {
0% {
border-right-color: #b6aaff;
border-bottom-color: #b6aaff;
opacity: 0;
}
20% {
opacity: 0.8;
}
}
@keyframes comment-blink-dark {
0% {
background-color: #473c8d;
opacity: 0;
}
20% {
opacity: 1;
}
}
@keyframes comment-blink-dark-after {
0% {
border-right-color: #473c8d;
border-bottom-color: #473c8d;
opacity: 0;
}
20% {
opacity: 1;
}
}
/* Themes */
.dark-theme .header-logo {
filter: invert(1) hue-rotate(180deg) brightness(2);
}
/* Light theme */
.light-theme {
color: #333333;
background-color: #eae9f2;
}
.light-theme .page-header {
background-color: #ffffff;
box-shadow: 0 2px 2px rgba(0, 0, 0, 0.2);
}
.light-theme .header-link {
color: #6653d9;
}
.light-theme .header-link::before {
background-image: url("img/arrow-back-light.svg");
background-repeat: no-repeat;
background-position: 0 0;
}
.light-theme .theme-button {
color: #6653d9;
border: 1px solid #6653d9;
}
.light-theme .theme-button::before {
background-image: url("img/moon-normal.svg");
}
.light-theme .theme-button:focus,
.light-theme .theme-button:hover {
color: #ffffff;
background-color: #6653d9;
}
.light-theme .theme-button:focus {
outline-color: #b6aaff;
}
.light-theme .theme-button:focus::before,
.light-theme .theme-button:hover::before {
background-image: url("img/moon-hover.svg");
}
.light-theme .menu-open {
background-color: #ffffff;
background-image: url("img/menu-open-light.svg");
}
.light-theme .menu:focus {
outline-color: #b6aaff;
}
.light-theme .menu-open:focus,
.light-theme .menu-open:hover {
background-color: #6653d9;
background-image: url("img/menu-open-dark.svg");
}
.light-theme .menu-close {
background-color: #6653d9;
}
.light-theme .menu-close:focus,
.light-theme .menu-close:hover {
background-color: #473c8d;
}
.light-theme .main-menu {
background-color: #6653d9;
color: #ffffff;
}
.light-theme .main-menu a:focus,
.light-theme .main-menu a:hover {
background-color: #473c8d;
}
.light-theme .main-menu a:focus {
outline-color: #b6aaff;
}
.light-theme .news-view button {
border: 1px solid #6653d9;
color: #6653d9;
}
.light-theme .news-view button:focus,
.light-theme .news-view button:hover,
.light-theme .news-view button:active,
.light-theme .news-view .view-checked {
background-color: #6653d9;
color: #ffffff;
}
.light-theme .news-view button:focus {
outline-color: #b6aaff;
}
.light-theme .news-view .row-view:focus::before,
.light-theme .news-view .row-view:hover::before,
.light-theme .news-view .row-view:active::before {
background-image: url("img/rows-light-checked.svg");
}
.light-theme .news-view .tile-view:focus::before,
.light-theme .news-view .tile-view:hover::before,
.light-theme .news-view .tile-view:active::before {
background-image: url("img/tiles-light-checked.svg");
}
.light-theme .row-view::before {
background-image: url("img/rows-light.svg");
}
.light-theme .tile-view::before {
background-image: url("img/tiles-light.svg");
}
.light-theme .row-view.view-checked::before {
background-image: url("img/rows-light-checked.svg");
}
.light-theme .tile-view.view-checked::before {
background-image: url("img/tiles-light-checked.svg");
}
.light-theme .new-block {
background-color: #ffffff;
box-shadow: 0 1px 4px rgba(0, 0, 0, 0.2);
}
.light-theme .news-full {
background-color: #ffffff;
box-shadow: 0 1px 4px rgba(0, 0, 0, 0.2);
}
.light-theme .new-block time {
color: #aaaaaa;
}
.light-theme .news-full time {
color: #aaaaaa;
}
.light-theme .cookies-agreement {
background-color: #fdeacd;
box-shadow: 0 -1px 4px rgba(0, 0, 0, 0.2);
}
.light-theme .button {
background-color: #6653d9;
color: #ffffff;
}
.light-theme .button:focus,
.light-theme .button:hover {
background-color: #473c8d;
}
.light-theme .button:focus {
outline-color: #b6aaff;
}
.light-theme .page-footer {
background-color: #6653d9;
color: #ffffff;
}
.light-theme .subscription,
.light-theme .comment-form {
background-color: #ffffff;
box-shadow: 0 1px 4px rgba(0, 0, 0, 0.2);
}
.light-theme .subscription-message {
background-color: #6653d9;
color: #eae9f2;
}
.light-theme .subscription-message::before {
background-image: url("img/icon-ok-light.svg");
}
.light-theme .subscription-label,
.light-theme .comment-label {
color: #6653d9;
}
.light-theme .subscription-email,
.light-theme .comment-field {
border: 1px solid #eae9f2;
color: #333333;
}
.light-theme .heart {
color: #6653d9;
background-image: url("img/icon-heart-light.svg");
opacity: 0.7;
}
.light-theme .heart.added {
background-image: url("img/icon-heart-light-added.svg");
}
.page .heart:focus,
.page .heart:hover {
opacity: 1;
}
.light-theme .heart:focus {
outline-color: #b6aaff;
}
.light-theme .heart:active {
opacity: 1;
background-image: url("img/icon-heart-light-active.svg");
}
.light-theme .comment-list li {
background-color: #ffffff;
}
.light-theme .user-comment:not(:first-child) {
animation: comment-blink-light 600ms ease-in;
}
.light-theme .user-comment::before {
border-right-color: #eae9f2;
color: #cdcdcd;
}
.light-theme .user-comment::after {
border-right-color: #ffffff;
border-bottom-color: #ffffff;
}
.light-theme .user-comment:not(:first-child)::after {
animation: comment-blink-light-after 600ms ease-in;
}
.light-theme .comment-label {
background-color: #ffffff;
}
.light-theme .comment-field:focus {
outline-color: #b6aaff;
}
/* Dark theme */
.dark-theme {
color: #f2f2f2;
background-color: #17161a;
}
.dark-theme .page-header {
background-color: #373540;
box-shadow: 0 2px 2px rgba(0, 0, 0, 0.6);
}
.dark-theme .header-link {
color: #9484f2;
}
.dark-theme .header-link::before {
background-image: url("img/arrow-back-dark.svg");
background-repeat: no-repeat;
background-position: 0 0;
}
.dark-theme .theme-button {
color: #9484f2;
border: 1px solid #9484f2;
}
.dark-theme .theme-button::before {
background-image: url("img/sun-normal.svg");
}
.dark-theme .theme-button:focus,
.dark-theme .theme-button:hover {
color: #17161a;
background-color: #9484f2;
}
.dark-theme .theme-button:focus {
outline-color: #6653d9;
}
.dark-theme .theme-button:focus::before,
.dark-theme .theme-button:hover::before {
background-image: url("img/sun-hover.svg");
}
.dark-theme .menu:focus {
outline-color: #6653d9;
}
.dark-theme .menu-open {
background-color: #373540;
background-image: url("img/menu-open-dark.svg");
}
.dark-theme .menu-open:focus,
.dark-theme .menu-open:hover {
background-color: #473c8d;
background-image: url("img/menu-open-dark.svg");
}
.dark-theme .menu-close {
background-color: #473c8d;
}
.dark-theme .menu-close:focus,
.dark-theme .menu-close:hover {
background-color: #6653d9;
}
.dark-theme .main-menu {
background-color: #473c8d;
color: #f2f2f2;
}
.dark-theme .main-menu a:focus {
outline-color: #6653d9;
}
.dark-theme .main-menu a:focus,
.dark-theme .main-menu a:hover {
background-color: #6653d9;
}
.dark-theme .news-view button {
border: 1px solid #9484f2;
color: #9484f2;
}
.dark-theme .news-view button:focus {
outline-color: #6653d9;
}
.dark-theme .news-view button:focus,
.dark-theme .news-view button:hover,
.dark-theme .news-view button:active,
.dark-theme .news-view .view-checked {
background-color: #9484f2;
color: #17161a;
}
.dark-theme .news-view .row-view:focus::before,
.dark-theme .news-view .row-view:hover::before,
.dark-theme .news-view .row-view:active::before {
background-image: url("img/rows-dark-checked.svg");
}
.dark-theme .news-view .tile-view:focus::before,
.dark-theme .news-view .tile-view:hover::before,
.dark-theme .news-view .tile-view:active::before {
background-image: url("img/tiles-dark-checked.svg");
}
.dark-theme .row-view::before {
background-image: url("img/rows-dark.svg");
}
.dark-theme .tile-view::before {
background-image: url("img/tiles-dark.svg");
}
.dark-theme .row-view.view-checked::before {
background-image: url("img/rows-dark-checked.svg");
}
.dark-theme .tile-view.view-checked::before {
background-image: url("img/tiles-dark-checked.svg");
}
.dark-theme .new-block {
background-color: #2a2930;
box-shadow: 0 1px 4px rgba(0, 0, 0, 0.6);
}
.dark-theme .news-full {
background-color: #2a2930;
box-shadow: 0 1px 4px rgba(0, 0, 0, 0.6);
}
.dark-theme .new-block time {
color: #888888;
}
.dark-theme .news-full time {
color: #888888;
}
.dark-theme .cookies-agreement {
background-color: #473c8d;
box-shadow: 0 -1px 4px rgba(0, 0, 0, 0.6);
}
.dark-theme .button {
background-color: #9484f2;
color: #17161a;
}
.dark-theme .button:focus {
outline-color: #6653d9;
}
.dark-theme .button:focus,
.dark-theme .button:hover {
background-color: #b6aaff;
}
.dark-theme .page-footer {
background-color: #0a0910;
color: #f2f2f2;
}
.dark-theme .subscription,
.dark-theme .comment-form {
background-color: #2a2930;
box-shadow: 0 1px 4px rgba(0, 0, 0, 0.6);
}
.dark-theme .subscription-message {
background-color: #9484f2;
color: #17161a;
}
.dark-theme .subscription-message::before {
background-image: url("img/icon-ok-dark.svg");
}
.dark-theme .subscription-label,
.dark-theme .comment-label {
color: #9484f2;
}
.dark-theme .comment-label {
background-color: #2a2930;
}
.dark-theme .subscription-email,
.dark-theme .comment-field {
border: 1px solid #473c8d;
color: #f2f2f2;
}
.dark-theme .heart {
color: #9484f2;
background-image: url("img/icon-heart-dark.svg");
opacity: 0.7;
}
.dark-theme .heart:focus {
outline-color: #6653d9;
}
.dark-theme .heart.added {
background-image: url("img/icon-heart-dark-added.svg");
}
.dark-theme .heart:active {
opacity: 1;
background-image: url("img/icon-heart-dark-active.svg");
}
.dark-theme .comment-list li {
background-color: #2a2930;
}
.dark-theme .user-comment:not(:first-child) {
animation: comment-blink-dark 600ms ease-in;
}
.dark-theme .user-comment::before {
border-right-color: #17161a;
color: rgba(255, 255, 255, 0.3);
}
.dark-theme .user-comment::after {
border-right-color: #2a2930;
border-bottom-color: #2a2930;
}
.dark-theme .user-comment:not(:first-child)::after {
animation: comment-blink-dark-after 600ms ease-in;
}
.dark-theme .comment-field:focus {
outline-color: #6653d9;
}
let heart = document.querySelector('.heart');
// Declare a variable here
heart.onclick = function () {
// Add the code here
heart.classList.toggle('added');
};
let page = document.querySelector('.page');
let themeButton = document.querySelector('.theme-button');
themeButton.onclick = function () {
page.classList.toggle('light-theme');
page.classList.toggle('dark-theme');
};
Thanks! We’ll fix everything at once!
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100%
Console
- In the code editor, click the
All filestab and select thelikes.jsfile . - In
likes.json line 2 declare a variablelikesNumberusingletand write an element to it with the classlikes-numberthat was found using thequerySelectormethod. - On the next line, declare a variable named
counterusing and assign it the value0. - Inside the handler, at the very beginning, assign
likesNumber.textContentthe valuecounter. - In the mini-browser, click the “heart” button. Please note that a number has now appeared next to the icon.
Comments