![[The AI Show Episode 142]: ChatGPT’s New Image Generator, Studio Ghibli Craze and Backlash, Gemini 2.5, OpenAI Academy, 4o Updates, Vibe Marketing & xAI Acquires X](https://www.marketingaiinstitute.com/hubfs/ep%20142%20cover.png)
![[FREE EBOOKS] The Kubernetes Bible, The Ultimate Linux Shell Scripting Guide & Four More Best Selling Titles](https://www.javacodegeeks.com/wp-content/uploads/2012/12/jcg-logo.jpg){kind=logo}
![From drop-out to software architect with Jason Lengstorf [Podcast #167]](https://cdn.hashnode.com/res/hashnode/image/upload/v1743796461357/f3d19cd7-e6f5-4d7c-8bfc-eb974bc8da68.png?#)
.png?#)
.jpg?#)
 (1).webp?#)
_Christophe_Coat_Alamy.jpg?#)
![Rapidus in Talks With Apple as It Accelerates Toward 2nm Chip Production [Report]](https://www.iclarified.com/images/news/96937/96937/96937-640.jpg)
The Hidden Costs of JavaScript Execution: How to Optimize for Speed
JavaScript is powerful, but it comes at a cost. While we often focus on network payload size and reducing dependencies, the hidden costs of JavaScript execution can significantly impact performance. This post explores these hidden costs and provides optimization strategies to ensure faster and smoother web experiences. Understanding the Execution Costs When JavaScript runs in the browser, it goes through multiple phases: Parsing & Compilation – The JavaScript engine parses the script and compiles it into bytecode. Execution – The engine executes the compiled bytecode. Garbage Collection (GC) – Unused memory is freed by the engine. Repaints & Layout Shifts – DOM manipulations trigger reflows and repaints, affecting rendering performance. Each of these steps adds overhead, and excessive JavaScript execution can lead to slowdowns, janky interactions, and unresponsive pages. Key Performance Pitfalls 1. Blocking the Main Thread JavaScript runs on the main thread by default. Long-running tasks block user interactions and delay rendering.
JavaScript is powerful, but it comes at a cost. While we often focus on network payload size and reducing dependencies, the hidden costs of JavaScript execution can significantly impact performance. This post explores these hidden costs and provides optimization strategies to ensure faster and smoother web experiences.
Understanding the Execution Costs
When JavaScript runs in the browser, it goes through multiple phases:
- Parsing & Compilation – The JavaScript engine parses the script and compiles it into bytecode.
- Execution – The engine executes the compiled bytecode.
- Garbage Collection (GC) – Unused memory is freed by the engine.
- Repaints & Layout Shifts – DOM manipulations trigger reflows and repaints, affecting rendering performance.
Each of these steps adds overhead, and excessive JavaScript execution can lead to slowdowns, janky interactions, and unresponsive pages.
Key Performance Pitfalls
1. Blocking the Main Thread
JavaScript runs on the main thread by default. Long-running tasks block user interactions and delay rendering.
