HTML id Attribute

The id attribute is used to define a unique identifier for an HTML element. It is commonly used to point to a style in a style sheet, as well as anchor links and targets for scripts. The id value is case-sensitive and should be unique within the HTML document.

This attribute can be used by CSS and JavaScript (via the HTML DOM) to perform specific tasks for the element with the specified id.

In CSS, you must write a hash ( # ) character followed by the id of the element for selecting the element with a specified id. It must have at least one character, and must not contain whitespace (tabs, spaces, etc.).

In HTML5, the id attribute can be used for any HTML element.

In HTML 4.01, the id attribute cannot be used with the following elements: <head>, <html>, <base>, <param>, <style>, <script>, and <title>.

Syntax

<tag id="id"></tag>

Example of the HTML id attribute:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      #grey {
        color: grey;
      }
      #purple {
        color: purple;
      }
    </style>
  </head>
  <body>
    <h1>Example of the HTML class attribute</h1>
    <p id="grey">
      It is a some red paragraph.
    </p>
    <p>This is a some text.</p>
    <p id="purple">
      It is a some yellow paragraph.
    </p>
  </body>
</html>

An HTML element can have only one unique id belonging to that single element unlike the class attribute where a class name can be used by multiple elements.

Example of the HTML id and class attributes:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      #green-bg {
        background-color: green;
        color: white;
        padding: 20px;
        text-align: center;
      }
      .text-grey {
        color: grey;
        padding: 5px 15px;
      }
    </style>
  </head>
  <body>
    <h1>Example of the HTML "id" and "class" attributes:</h1>
    <p>
      Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book.
    </p>
    <h2 id="green-bg">HTML ID attribute</h2>
    <p class="text-grey">
      Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs.
    </p>
    <p class="text-grey">
      Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book
    </p>
    <p class="text-grey">
      The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book.
    </p>
  </body>
</html>

Bookmarks

You can use HTML bookmarks to allow readers to jump to other parts of a web page when it is too long.

To add a bookmark, first, create the bookmark and then add a link to it. When you click on the link, the page will scroll to the part with the bookmark.

Example of adding a bookmark:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      p {
        line-height: 1.5;
        color: #777777;
      }
      a {
        color: #20c7c1;
        display: inline-block;
        padding: 5px 15px;
      }
      strong {
        display: block;
        color: #1129dc;
      }
    </style>
  </head>
  <body>
    <h1>Example of the HTML "id" and "class" attributes:</h1>
    <p>Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book.</p>
    <a href="#text2">Jump to the text-2</a>
    <a href="#text3">Jump to the text-3</a>
    <p id="text-1">
      <strong>Text number 1</strong> Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs.
    </p>
    <p id="text2">
      <strong>Text number 2</strong> Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book. Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book
    </p>
    <p id="text3">
      <strong>Text number 3</strong> Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book.
    </p>
    <p>
      <strong>Text number 4</strong> Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book.
    </p>
    <p>
      <strong>Text number 5</strong> Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book.
    </p>
  </body>
</html>

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