ID Selector - O Level (NIELIT)

The CSS ID selector is used to style a single, unique element on a webpage. IDs are unique within a page, meaning each element should have only one ID.

Syntax

#idname {
    property: value;
}

Example

#header {
    background-color: black;
    color: white;
    padding: 20px;
    text-align: center;
}
/* Styling a unique button with the ID "submit-btn" */
#submit-btn {
    background-color: green;
    color: white;
    font-size: 16px;
}

Explanation

#header applies styles only to the element with ID "header".
#submit-btn applies styles only to the element with ID "submit-btn".

Example in HTML

<h1 id="header">Welcome to My Website</h1>
<button id="submit-btn">Submit</button>

Differences: ID vs. Class

Selector	Usage	Example
`#idname`	Unique for one element	`#header { color: red; }`
`.classname`	Reusable for multiple elements	`.button { color: blue; }`

Qus. 1 : Which of the following attribute is used to provide a unique name to an element?

class
id
type
None of the above

Qus. 2 : Which attribute specifies a unique alphanumeric identifier to be associated with an element?

class
id
article
html

Qus. 3 : Which of the following selectors select any tag with an id attribute set ?

E#id
.class
#id
*

Programs

HTML code using CSS to create a job application

View Solution