🔸id

🔰 JS ⟩ browser ⟩ DOM ⟩ types ⟩ Element ⟩ attribute ⟩ id

The id global attribute defines an identifier which must be unique in the whole document. Its purpose is to identify the element when ：

• linking (using a fragment identifier)

• scripting

• styling (with CSS)

⭐️ 重點

DOM element with "id" is automatically registerd as global variable/global object property.

📘 手冊

• HTML ⟩ Global attributes ⟩ id

• Web APIs ⟩ Element ⟩ .id

• CSS ⟩ ID selectors