Tarea anterior
Creación de elementos del DOM4/8
A la lista de tareas
  1. 1. Comentarios para un portal de noticias
  2. 2. El método append y la inserción de contenido
  3. 3. El método createElement y la creación de elementos
  4. 4. Añadimos un elemento a la página
  5. 5. Añadimos un comentario al enviar el formulario
  6. 6. Cambiamos las propiedades del elemento que creamos
  7. 7. Tomamos el texto del comentario del campo de entrada
  8. 8. Limpiamos el campo de entrada después de enviar
Siguiente tarea
  • Cursos
  • Registro
  • Iniciar sesión

Loading…
En unos segundos, estará listo.

  • Teoría
  • Teoría

Añadimos un elemento a la página

Hemos creado un nuevo elemento de lista y lo hemos mostrado en la consola. Pero en la página no aparece. La razón es simple: todavía no le hemos dicho a JavaScript dónde insertarlo. Mientras no lo hagamos, el elemento solo existe dentro del script.

Para indicar dónde debe colocarse el nuevo elemento, usamos el ya conocido método append:

// Creamos un elemento nuevo
let newElement = document.createElement('div');

// Buscamos el elemento padre
let parent = document.querySelector('.parent');

// Añadimos el nuevo elemento al final del elemento padre
parent.append(newElement);

En el portal de noticias, los comentarios nuevos deben aparecer al final del hilo. Esto es lo que obtendremos después de añadir el elemento que creamos:

<!-- Marcado inicial -->
<ol class="comment-list">
  <li class="user-comment">Venga ya, qué tontería...</li>
</ol>

<!-- Marcado en el navegador después de commentList.append(newComment) -->
<ol class="comment-list">
  <li class="user-comment">Venga ya, qué tontería...</li>
  <li></li>
</ol>

El método append no copia el elemento, sino que lo mueve. Si entre paréntesis pasas un elemento que ya está en la página, desaparecerá de su lugar anterior y aparecerá en el nuevo. No se puede insertar el mismo elemento varias veces en el marcado.

Todos los archivos
    <!DOCTYPE html> <html lang="es"> <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="Logotipo del portal FlashNews!"> </span> <button class="theme-button" type="button">Cambiar tema</button> </div> </header> <main class="inner-news"> <article class="container"> <h1 class="inner-heading">🔥 ¡Impacto! ¡Escándalo! ¡Sensación!</h1> <div class="news-full"> <img src="img/news-robot2.jpg" alt="Robot de vacaciones"> <div class="news-stats"> <button class="heart" type="button"><span class="likes-number">45</span></button> <time datetime="2019-12-22">22 dic 2019</time> </div> <p>Resulta que, para empezar a programar en JavaScript, no hace falta ser un gato. Un grupo de científicos creó el primer robot capaz de desarrollarse y cambiar su propio código. Enseguida aprendió a maquetar sitios web y se fue a trabajar como freelance a Bali.</p> </div> </article> <section class="comment-feed container"> <h2>Comentarios</h2> <ol class="comment-list"> <li class="user-comment">No puede ser, qué tontería...</li> </ol> <form action="https://echo.codigoheroe.com/courses" method="post" class="comment-form"> <div class="comment-inner"> <label class="comment-label" for="comment-input">Tu comentario</label> <input type="text" class="comment-field" placeholder="Comentario" required id="comment-input"> </div> <button class="button" type="submit">Enviar</button> </form> </section> </main> <footer class="page-footer"> <div class="container"> <p>© FlashNews!</p> <span class="footer-logo"> <img src="img/white-logo.svg" alt="Logotipo del portal FlashNews!"> </span> </div> </footer> <script src="themes.js"></script> <script src="likes.js"></script> <script src="comments.js"></script> </body> </html>
    /* estilos de la página de noticias */ .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; font-size: 24px; } .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; } } /* temas */ .dark-theme .header-logo { filter: invert(1) hue-rotate(180deg) brightness(2); } /* Tema claro */ .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; } /* Tema oscuro */ .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 commentForm = document.querySelector('.comment-form'); let commentList = document.querySelector('.comment-list'); commentForm.onsubmit = function (evt) { evt.preventDefault(); }; let newComment = document.createElement('li'); console.log(newComment);
    let page = document.querySelector('.page'); let themeButton = document.querySelector('.theme-button'); themeButton.onclick = function () { page.classList.toggle('light-theme'); page.classList.toggle('dark-theme'); };
    let heart = document.querySelector('.heart'); let likesNumber = document.querySelector('.likes-number'); heart.onclick = function () { if (heart.classList.contains('added')) { likesNumber.textContent--; } else { likesNumber.textContent++; } heart.classList.toggle('added'); };

    El código ha cambiado, haz clic en "Actualizar" o activa la ejecución automática.

    Ha ido a otra página

    Haga clic dentro del mininavegador para poner el foco en esta ventana.

    100%
    Consola
    ObjetivosRealizado
    0
      1. Elimina la salida a consola de la última línea.
      2. En esa misma línea, escribe una instrucción que añada el elemento newComment al final del hilo de comentarios.
        Fíjate en que el elemento creado ahora ya aparece en la página.

      © 2023-2026, codigoheroe.com