Element: before() method
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2018.
Thuộc tính Element.before() method inserts a set of
Node objects or strings in the children list of this
Element's parent, just before this Element.
Strings are inserted as equivalent Text nodes.
Cú pháp
js
before(param1)
before(param1, param2)
before(param1, param2, /* …, */ paramN)
Tham số
param1, …,paramN-
A set of
Nodeobjects or strings to insert.
Giá trị trả về
None (undefined).
Ngoại lệ
HierarchyRequestErrorDOMException-
Thrown when the node cannot be inserted at the specified point in the hierarchy.
Ví dụ
Inserting an element
js
let container = document.createElement("div");
let p = document.createElement("p");
container.appendChild(p);
let span = document.createElement("span");
p.before(span);
console.log(container.outerHTML);
// "<div><span></span><p></p></div>"
Inserting text
js
let container = document.createElement("div");
let p = document.createElement("p");
container.appendChild(p);
p.before("Text");
console.log(container.outerHTML);
// "<div>Text<p></p></div>"
Inserting an element and text
js
let container = document.createElement("div");
let p = document.createElement("p");
container.appendChild(p);
let span = document.createElement("span");
p.before(span, "Text");
console.log(container.outerHTML);
// "<div><span></span>Text<p></p></div>"
Đặc tả kỹ thuật
| Specification |
|---|
| DOM # ref-for-dom-childnode-before① |