{"id":1432,"date":"2024-08-02T06:25:42","date_gmt":"2024-08-02T04:25:42","guid":{"rendered":"https:\/\/blog.sutilweb.eu\/?page_id=1432"},"modified":"2024-08-02T06:25:42","modified_gmt":"2024-08-02T04:25:42","slug":"17-variables-con-css","status":"publish","type":"page","link":"https:\/\/sutilweb.eu\/index.php\/lenguajes\/css3\/css3-avanzado\/17-variables-con-css\/","title":{"rendered":"17. Variables con CSS"},"content":{"rendered":"\n

La funci\u00f3n var()<\/em><\/strong> es usada para insertar el valor de una variable CSS<\/strong>. Las variables CSS<\/strong> tienen acceso al DOM<\/strong>, lo que significa que puede crear variables con alcance local<\/strong> o global<\/strong>, cambiar las variables con JavaScript y cambiar las variables en funci\u00f3n de las consultas de medios. Una buena manera de usar las variables CSS<\/strong> es cuando se trata de los colores de tu dise\u00f1o. En lugar de copiar y pegar los mismos colores una y otra vez, puede colocarlos en variables.<\/p>\n\n\n\n\n\n\n\n

La manera tradicional<\/h2>\n\n\n\n

El siguiente ejemplo muestra la forma tradicional de definir algunos colores en una hoja de estilo (definiendo los colores a usar, para cada elemento espec\u00edfico).<\/p>\n\n\n\n

Ejm<\/strong><\/p>\n\n\n\n

<!DOCTYPE html>
<html>
  <head>
    <style>
      body {
        background-color: #1e90ff;
      }

      h2 {
        border-bottom: 2px solid #1e90ff;
      }

      .container {
        color: #1e90ff;
        background-color: #ffffff;
        padding: 15px;
      }

      button {
        background-color: #ffffff;
        color: #1e90ff;
        border: 1px solid #1e90ff;
        padding: 5px;
      }
    <\/style>
  <\/head>
  <body>
    <h1>The Traditional Way<\/h1>

    <div class=\"container\">
      <h2>Lorem Ipsum<\/h2>
      <p>
        Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam semper
        diam at erat pulvinar, at pulvinar felis blandit.
      <\/p>
      <p>
        Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam semper
        diam at erat pulvinar, at pulvinar felis blandit.
      <\/p>
      <p>
        <button>Yes<\/button>
        <button>No<\/button>
      <\/p>
    <\/div>
  <\/body>
<\/html><\/pre>\n\n\n\n
Sintaxis de la funci\u00f3n var()<\/h2>\n\n\n\n
La funci\u00f3n var()<\/em><\/strong> se usa para insertar el valor de una variable CSS. La sintaxis de la funci\u00f3n var()<\/em><\/strong> es la siguiente.<\/p>\n\n\n\n
var(--nombre, valor<\/em>)<\/pre>\n\n\n\n
Valor<\/th>Descripci\u00f3n<\/th><\/tr>
name<\/em><\/td>Requerido. El nombre de la variable (debe comenzar con dos guiones)<\/td><\/tr>
value<\/em><\/td>Opcional. El valor alternativo (utilizado si no se encuentra la variable)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\n
Nota<\/strong>: El nombre de la variable debe comenzar con dos guiones (–) y distingue entre may\u00fasculas y min\u00fasculas (es case sensitive).<\/p>\n<\/blockquote>\n\n\n\n
Como trabaja var()<\/h2>\n\n\n\n
En primer lugar, las variables CSS<\/strong> pueden tener un alcance global<\/strong> o local<\/strong>. Las variables globales<\/strong> se pueden acceder\/usar a trav\u00e9s de todo el documento, mientras que las variables locales<\/strong> se pueden usar solo dentro del selector donde se declara. Para crear una variable con alcance global<\/strong>, decl\u00e1rala dentro del selector :root<\/em><\/strong>. El selector :root<\/em> <\/strong>coincide con el elemento ra\u00edz del documento. Para crear una variable con alcance local<\/strong>, decl\u00e1rala dentro del selector que la va a usar. El siguiente ejemplo es igual al ejemplo anterior, pero aqu\u00ed usamos la funci\u00f3n var()<\/em><\/strong>. Primero, declaramos dos variables globales (–blue<\/em> <\/strong>y —white<\/em><\/strong>). Luego, usamos la funci\u00f3n var()<\/em><\/strong> para insertar el valor de las variables m\u00e1s adelante en la hoja de estilo.<\/p>\n\n\n\n
Ejm<\/strong><\/p>\n\n\n\n
<!DOCTYPE html>
<html lang=\"es\">
  <head>
    <style>
      :root {
        --blue: #1e90ff;
        --white: #ffffff;
      }

      body {
        background-color: var(--blue);
      }

      h1 {
        color: var(--white);
      }

      h2 {
        border-bottom: 2px solid var(--blue);
      }

      .container {
        color: var(--blue);
        background-color: var(--white);
        padding: 15px;
      }

      button {
        background-color: var(--white);
        color: var(--blue);
        border: 1px solid var(--blue);
        padding: 5px;
      }
    <\/style>
  <\/head>
  <body>
    <h1>Usando la funci\u00f3n var()<\/h1>
    <div class=\"container\">
      <h2>Lorem Impsum<\/h2>
      <p>Algo de texto escrito<\/p>
      <p>M\u00e1s texto escrito<\/p>
      <button>Yes<\/button>
      <button>No<\/button>
    <\/div>
  <\/body>
<\/html><\/pre>\n\n\n\n
Las ventajas de usar var()<\/em><\/strong> son:<\/p>\n\n\n\n
    \n
  • Hace el c\u00f3digo m\u00e1s f\u00e1cil de leer.<\/li>\n\n\n\n
  • Hace mucho m\u00e1s f\u00e1cil cambiar el valor de los colores.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
    La funci\u00f3n var() es usada para insertar el valor de una variable CSS. Las variables CSS tienen acceso al DOM, lo que significa que puede crear variables con alcance local o global, cambiar las variables con JavaScript y cambiar las variables en funci\u00f3n de las consultas de medios. Una buena manera de usar las variables […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1367,"menu_order":16,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"class_list":["post-1432","page","type-page","status-publish","hentry"],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false},"uagb_author_info":{"display_name":"Sutil Web","author_link":"https:\/\/sutilweb.eu\/index.php\/author\/sutilweb\/"},"uagb_comment_info":0,"uagb_excerpt":"La funci\u00f3n var() es usada para insertar el valor de una variable CSS. Las variables CSS tienen acceso al DOM, lo que significa que puede crear variables con alcance local o global, cambiar las variables con JavaScript y cambiar las variables en funci\u00f3n de las consultas de medios. Una buena manera de usar las variables…","_links":{"self":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1432","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/comments?post=1432"}],"version-history":[{"count":2,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1432\/revisions"}],"predecessor-version":[{"id":1434,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1432\/revisions\/1434"}],"up":[{"embeddable":true,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1367"}],"wp:attachment":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/media?parent=1432"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}