CSS Interview Questions
HTML & CSS
Web DevelopmentFrontendQuestion 3
How do you apply a style to an element using an ID selector?
Answer:
To apply a style to an element using an ID selector in CSS, you need to follow these steps:
1. Assign an ID to the HTML Element
First, assign a unique id
attribute to the HTML element you want to style. The id
should be unique within the document.
<p id="myParagraph">This is a paragraph.</p>
2. Create a CSS Rule with an ID Selector
In your CSS, create a rule that uses the ID selector to target the specific element. The ID selector is created by prefixing the ID value with a #
symbol.
#myParagraph {
color: blue;
font-size: 16px;
font-weight: bold;
}
3. Apply the CSS
The styles defined in the CSS rule will be applied to the element with the matching ID.
Example: Full HTML Document with an ID Selector
Here's how it looks when put together in an HTML document:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>ID Selector Example</title>
<style>
/* ID selector */
#myParagraph {
color: blue;
font-size: 16px;
font-weight: bold;
}
</style>
</head>
<body>
<!-- The paragraph with the ID "myParagraph" will be styled according to the CSS rule above -->
<p id="myParagraph">This is a paragraph.</p>
</body>
</html>
Key Points
- The
id
attribute in HTML must be unique within a document. You should not assign the same ID to multiple elements. - The ID selector in CSS is case-sensitive, meaning
#myParagraph
is different from#myparagraph
. - The ID selector has a higher specificity than class selectors and element selectors, which means it will override styles applied by those selectors if there is a conflict.