Id

Definition: In HTML markup formatting, the id attribute is a unique identifier assigned to an element within a web page.

Usage: The id attribute is commonly used to target specific elements when applying CSS styles or JavaScript interactions. It helps in distinguishing individual elements from one another within the page.

Syntax: The id attribute is added to an HTML element using the following syntax:

<element id="unique-identifier">Content</element>

Example:

<p id="intro">This is the introduction paragraph.</p>
<div id="main-content">This is the main content of the page.</div>
<button id="submit-btn">Submit</button>

Note: The identifier specified in the id attribute must be unique within the entire HTML document, hence it should not be repeated on other elements.