創(chuàng)建一個(gè)新的HTML DOM 節(jié)點(diǎn)元素
To add a new element to the HTML DOM, you must create the element (element node) first, and then append it to an existing element.
為了添加一個(gè)新的element,必須提前創(chuàng)建一個(gè)節(jié)點(diǎn)，然后把它綁定到已經(jīng)存在的一個(gè)元素節(jié)點(diǎn)上；
例子：
This is a paragraph.
This is another paragraph.
var para = document.createElement("p");
var node = document.createTextNode("This is new.");
para.appendChild(node);
var element = document.getElementById("div1");
element.appendChild(para);
例子解讀：
This code creates a new
element:
var para = document.createElement("p");
To add text to the element, you must create a text node first. This code creates a text node:
var node = document.createTextNode("This is a new paragraph.");
Then you must append the text node to the element:
para.appendChild(node);
Finally you must append the new element to an existing element.This code finds an existing element:
var element = document.getElementById("div1");
This code appends the new element to the existing element:
element.appendChild(para);
Creating new HTML Elements - insertBefore()
The appendChild() method in the previous example, appended the new element as the last child of the parent.
If you don't want that you can use the insertBefore() method:
Example
This is a paragraph.
This is another paragraph.
var para = document.createElement("p");
var node = document.createTextNode("This is new.");
para.appendChild(node);
var element = document.getElementById("div1");
var child = document.getElementById("p1");
element.insertBefore(para,child);
Removing Existing HTML Elements
To remove an HTML element, you must know the parent of the element:
Example
This is a paragraph.
This is another paragraph.
var parent = document.getElementById("div1");
var child = document.getElementById("p1");
parent.removeChild(child);
The method node.remove() is implemented in the DOM 4 specification.
But because of poor browser support, you should not use it.
Example Explained
This HTML document contains a
element with two child nodes (two
elements):
This is a paragraph.
This is another paragraph.
Find the element with id="div1":
var parent = document.getElementById("div1");
Find theelement with id="p1":
var child = document.getElementById("p1");
Remove the child from the parent:
parent.removeChild(child);
It would be nice to be able to remove an element without referring to the parent.
But sorry. The DOM needs to know both the element you want to remove, and its parent.
Here is a common workaround: Find the child you want to remove, and use its parentNode property to find the parent:
var child = document.getElementById("p1");
child.parentNode.removeChild(child);
Replacing HTML Elements （替換元素）
To replace an element to the HTML DOM, use the replaceChild() method:
Example
This is a paragraph.
This is another paragraph.
var para = document.createElement("p");
var node = document.createTextNode("This is new.");
para.appendChild(node);
var parent = document.getElementById("div1");
var child = document.getElementById("p1");
parent.replaceChild(para,child);
