document.getElementById & document.querySelector

document.getElementById & document.querySelector

https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelectorAllcode

https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelectorblog

https://developer.mozilla.org/en-US/docs/Web/API/Document/getElementById繼承

  1. getElementById 僅支持 id 選擇器, 返回 An Element object接口

  2. querySelector 支持各類選擇器, 返回匹配的第一個 An HTMLElement objectelement

https://developer.mozilla.org/en-US/docs/Web/API/Elementget

https://developer.mozilla.org/en-US/docs/Web/API/HTMLElementio

  1. HTMLElement 是父類,base 接口
  2. Element 是子類,實現/繼承於 HTMLElement 接口

demo

document.getElementById("demo");
<section id=​"demo">​

​</section>​
document.querySelector("#demo")
<section id=​"demo">​

​</section>​
document.querySelectorAll("#demo")
NodeList [section#demo]0: section#demolength: 1__proto__: NodeList
document.getElementById("demo") === document.querySelector("#demo")
true
document.getElementById("demo") == document.querySelector("#demo")
true
typeof document.getElementById("demo")
"object"
typeof document.querySelector("#demo")
"object"
相關文章
相關標籤/搜索