Master JavaScript Event Propagation: Bubbling & Capturing (2026 Interview Prep)

In this comprehensive 2026 guide, we master the essentials of JavaScript Event Propagation. Whether you are a beginner or a senior developer preparing for a technical interview, understanding the "order of operations" for events is critical. We break down the three core phases of propagation - Bubbling, Capturing (Trickling), and Delegation - using clear, visual examples and real-world code snippets. ⏱️ Chapters 00:00 Intro 00:45 What is Event Propagation? 01:50 HTML & CSS Setup for Examples 02:30 Default Behavior: Event Bubbling 03:45 event.target vs. event.currentTarget vs. this 05:10 Deep Dive into Event Capturing (Trickling) 06:25 The Shortcut: Third Parameter Options 07:40 Tricky Interview Question: Custom Propagation Order 09:15 Summary & Final Interview Tips What you will learn: ✓ The Fundamentals: What "propagation" actually means in the context of the DOM. ✓ Event Bubbling: Why events move from child to parent by default (and how to visualize it like soap bubbles). ✓ Event Capturing: How to reverse the flow to move from the top down using the capture property. ✓ Target vs. CurrentTarget: Learn the difference between the element that triggered the event and the element currently handling it. ✓ The "this" Keyword: Why this is identical to event.currentTarget in event listeners. ✓ Interview Logic: How to handle tricky requirements, such as making a parent fire after a child but before a grandparent. 📚 Resources & Links 🚀 Get the Code: https://github.com/logicbaselabs/event-propagation 🔗 Event Delegation - https://youtu.be/VDMWWPnrbkY Connect with me: 🔗 My Website - https://www.sumitsaha.me 🔗 Facebook Page - https://facebook.com/@logicBaseLabs 🔗 LinkedIn Page - https://www.linkedin.com/company/logicbaselabs 🔗 X - https://x.com/@logicBaseLabs