HTML and Browser Event

1. What is sementric html? Why do some people think it's useful?

https://www.wikiwand.com/en/Semantic_HTML

2. What is event bubbling and capturing?

Ref: http://www.quirksmode.org/js/events_order.html

3 What event doesn't bubble?

Any events specific to one element do not bubble: submit, focus, blur, load, unload, change, reset, scroll, most of the DOM events (DOMFocusIn, DOMFocusOut, DOMNodeRemoved, etc), mouseenter, mouseleave, etc

Ref: http://stackoverflow.com/questions/5574207/html-dom-which-events-do-not-bubble

4. How to cancel a <a> event using coding?

event.preventDefault();

Ref: http://stackoverflow.com/questions/10276133/how-to-disable-html-links