What is the most efficient way to select a single element with a specific ID?
document.getElementById('elementId') is the most efficient way to select a single element with a specific ID. It's purpose-built for this exact task and is generally faster than querySelector('#elementId') because it doesn't need to parse and process CSS selector syntax. The browser has internal optimizations specifically for getElementById(), making it the preferred method when you know you're looking for a single element by ID.