CSS #id Selector

Posted in CSS Tutorial

Updated on Oct 27, 2024

By Mari Selvan

👁️ 17 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

The CSS #id selector is used to style an element based on its unique id attribute. IDs are meant to be unique within a webpage, and this selector allows you to target a specific element by its id value. This provides a precise way to apply styles to a single element, distinguishing it from other elements in the document.

💡 Syntax

The signature of the #id Selector is as follows:

Syntax

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#elementID {
    /* CSS properties */
}

#elementID refers to the id of the HTML element you want to style.
In CSS, the id selector is prefixed with a # followed by the id name.

📝 Example

Here is an example of how to use the CSS #id selector:

☠️ HTML

HTML

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS #id Selector Example</title>
    <link rel="stylesheet" href="styles.css">
</head>
<body>
    <h1 id="main-title">Welcome to My Blog</h1>
    <p>This is a paragraph about the blog.</p>
    <p id="highlight">This paragraph is uniquely styled.</p>
</body>
</html>

🎨 CSS

CSS

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/* Styling the element with id "main-title" */
#main-title {
    font-size: 36px;
    color: darkblue;
    text-align: center;
}

/* Styling the element with id "highlight" */
#highlight {
    background-color: yellow;
    font-weight: bold;
}

In this example:

The <h1> element with the id="main-title" is styled with a larger font size, dark blue color, and centered alignment.
The <p> element with id="highlight" is styled with a yellow background and bold font.

💬 Usage Tips

Uniqueness: An id should be unique within a document. Do not assign the same id to multiple elements as it can cause unpredictable results.
Specificity: The #id selector has a higher specificity compared to class selectors (.class). It overrides styles applied by less specific selectors like element selectors (element) or class selectors (.class).
Avoid overusing id: It's best to reserve the id selector for elements that require unique styles or behaviors, like #header or #footer. For reusable styles, use classes (.class).

⚠️ Common Pitfalls

Multiple elements with the same id: The id must be unique in an HTML document. If more than one element shares the same id, browsers may not apply styles correctly.
Over-relying on id: While the #id selector is powerful, relying too much on it can reduce flexibility in your CSS. For styles that may apply to multiple elements, prefer using classes.
Specificity issues: Since #id has high specificity, it can sometimes conflict with other styles, especially if you are using complex CSS rules. Be mindful of this to avoid unexpected behavior.

🎉 Conclusion

The CSS #id selector is an essential tool for targeting and styling unique elements on a webpage. While it’s powerful due to its high specificity, it should be used with care to maintain clean, maintainable CSS.

By understanding how to use the #id selector effectively, you can create precise and impactful styles for specific elements on your page.