Which attribute is used to provide a unique identifier for an HTML element?*identifieridclassname

The attribute used to provide a unique identifier for an HTML element is the id attribute.

Explanation

1. Purpose of the id Attribute: The id attribute serves as a unique identifier for elements within an HTML document. This means that no two elements should have the same id value in the same document. It allows for specific targeting of an element, which can be beneficial for CSS styling and JavaScript functionality.

2. Usage in HTML: The id attribute is defined within an HTML tag. For example: <div id="uniqueElement">Content here</div>. In this case, uniqueElement is the identifier for this particular <div> element.

3. Advantages: By using id, developers can reference the element through CSS or JavaScript easily. CSS can style the element using the # symbol (e.g., #uniqueElement { color: blue; }), and JavaScript can manipulate it using document methods like document.getElementById('uniqueElement').

4. Comparison with Other Attributes: Unlike the class attribute, which can be shared by multiple elements, each id value must be unique within the page. This distinction is crucial for developers to ensure proper element identification and manipulation.

Therefore, the correct answer to the question is id.