Which of the following is most likely to block page interactivity?
- Inline CSS
- Large video files
- Unoptimized images
- Heavy JavaScript execution
Explanation: Heavy JavaScript execution is most likely to block page interactivity. When JavaScript code is executing, it can tie up the browser’s main thread, preventing it from responding to user input or updating the page’s display. This delay in responsiveness can lead to a poor user experience, especially on slower devices or networks. Heavy JavaScript execution can occur due to several reasons, including executing long-running scripts, excessive DOM manipulation, or inefficient code. To mitigate this issue and ensure smooth page interactivity, developers should optimize their JavaScript code by reducing its size, minimizing long-running operations, and deferring non-critical scripts. Additionally, using web workers or asynchronous programming techniques can help offload intensive JavaScript tasks to background threads, allowing the main thread to remain responsive. By addressing heavy JavaScript execution, developers can enhance the responsiveness and usability of their web pages, leading to a more satisfying user experience overall.