Getting elements by class name allows you to select and manipulate multiple elements that share the same CSS class, perfect for batch operations. As the creator of CoreUI, a widely used open-source UI library, I’ve used class-based selection extensively for styling updates and event handling across multiple components. From my expertise, document.getElementsByClassName() is the most straightforward method for selecting elements by class. This approach returns a live HTMLCollection that automatically updates when the DOM changes.

Getting elements by ID is the most direct way to select specific HTML elements for manipulation, styling, or event handling. As the creator of CoreUI, a widely used open-source UI library, I’ve used element selection extensively for interactive component functionality. From my expertise, document.getElementById() is the fastest and most reliable method for selecting elements with unique IDs. This approach provides direct access to specific elements without the overhead of more complex selectors.

Accessing the last element of arrays is essential for retrieving the most recent item, implementing stack operations, and getting final values in data processing within JavaScript applications. With over 25 years of experience in software development and as the creator of CoreUI, I’ve accessed last elements extensively in components like activity feeds, pagination controls, and timeline displays where the final item often represents the current state or latest entry. From my extensive expertise, the most reliable and universally supported approach is using array index notation with array.length - 1 to access the final position. This method is dependable, works across all JavaScript versions, and clearly expresses the intent to access the last element.

Accessing the first element of arrays is fundamental for processing data sequences, implementing queue operations, and retrieving initial values in JavaScript applications. With over 25 years of experience in software development and as the creator of CoreUI, I’ve accessed first elements countless times in components like breadcrumb navigation, carousel displays, and data lists where the initial item often has special significance or styling. From my extensive expertise, the most straightforward and universally supported approach is using array index notation with [0] to access the first position. This method is direct, readable, and works consistently across all JavaScript environments without any dependencies.