Native js operation dom-JS Tutorial-php.cn

In this article, we will share with you how to operate dom using native js. We hope it will be useful to everyone.

ng-click="brandFnc($event)"$scope.brandFnc = function($event) {
    // 通过 $event.target 来获取
}
ev.target.parentElementev.target.parentElement.children[0].srcev.target.previousElementSiblingev.target.nodeNameconsole.log(ev.target.outerHTML);//<button ng-click="ngGetSrc($event)">获取src</button>---整个console.log(ev.target.innerHTML);//获取src--中间的内容原生js的方法:1)创建节点：createElement创建元素，
也可以使用createTextNode创建文本节点.
document.body指向的是<body>元素;document.documentElement则指向<html>元素
    //创建节点
    var createNode = document.createElement("p");
    var createTextNode = document.createTextNode("hello world");
    createNode.appendChild(createTextNode);
    document.body.appendChild(createNode);
    document.documentElement.appendChild(createNode);2)插入节点：appendChild，insertBefore，
insertBefore接收两个参数，第一个是插入的节点，第二个是参照节点，如insertBefore(a,b)，则a会插入在b的前面
//插入节点
 var createNode = document.createElement("p");var createTextNode = document.createTextNode("hello world");
  createNode.appendChild(createTextNode);
 var p1 = document.getElementById("p1");
 document.body.insertBefore(createNode,p1);3)替换和删除元素，从replaceChild和removeChild的字面意思看，就是删除子节点，因此调用者，需要包含子节点p1，不然调用会报错。返回的节点是替换的或删除的元素，被替换/删除的元素仍然存在，但document中已经没有他们的位置了。
//替换元素
var replaceChild = document.body.replaceChild(createNode,p1);//删除元素
var removeChild = document.body.removeChild(p1);4)节点的属性：firstChild:第一个子节点lastChild:最后一个子节点childNodes:子节点集合，获取其中子节点可以someNode.childNodes[index]或者someNode.childNodes.item(index)nextSibling:下一个兄弟节点
previousSibling：上一个兄弟节点
parentNode：父节点
<ul id="ul"><li>sdsssssss</li><li>qqqq</li><li>wwww</li><li>eeee</li></ul>
复制代码
   //节点属性
    var ul = document.getElementById("ul");
    var firstChild = ul.firstChild;
    console.log(firstChild.innerHTML);
    var lastChild = ul.lastChild;
    console.log(lastChild.innerHTML);
    var length = ul.childNodes.length;
    console.log(length);
    var secondChild = ul.childNodes.item(1);
    console.log(secondChild.innerHTML);
    var forthChild = ul.childNodes.item(2).nextSibling;
    console.log(forthChild.innerHTML);
    var thridChild = forthChild.previousSibling;
    console.log(thridChild.innerHTML);
    var parentNode = forthChild.parentNode;
    console.log(parentNode.innerHTML);5) 文档片段，好处在于减少dom的渲染次数，可以优化性能。
//文本片段
    var fragment = document.createDocumentFragment();
    var ul = document.getElementById("ul");
    var li = null;
    for (var i = 4; i >= 0; i--) {
        li = document.createElement("li");
        li.appendChild(document.createTextNode("item "+i));
        fragment.appendChild(li);
    }
    ul.appendChild(fragment);6）克隆元素
someNode.cloneNode(true):深度克隆，会复制节点及整个子节点
someNode.cloneNode(false):浅克隆，会复制节点，但不复制子节点 
//克隆
    var clone = ul.cloneNode(true);

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document.body.appendChild(clone);

Note: 1. There are cross-browser issues with childNodes.length

You can see the relevant list The html fragment is not written in the format of

<ul id="ul">
<li>sdsssssss</li>
<li>qqqq</li>
<li>wwww</li>
<li>eeee</li>
</ul>

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but is written in a format without line breaks because the results of obtaining ul.childNodes.length are different in different browsers:
In ie, ul.childNodes.length does not calculate the newline space between li, resulting in a value of 4. In ff, chrome, and safari, there will be 5 text nodes containing the whitespace between li, so ul. childNodes.length is 9. To solve the cross-browser problem, you can remove the line breaks between li and change it to a one-line writing format.
2. CloneNode has cross-browser issues
In IE, elements copied through the cloneNode method will copy the event handler, for example, var b = a.cloneNode(true). If a has click, mouseover Wait for event monitoring, then b will also have these event monitoring.

In ff, chrome, and safari, the elements copied through the cloneNode method will only copy the attributes, and nothing else will be copied.
Therefore, to solve the cross-browser problem, it is best to copy the elements before copying. It's best to remove the event handler first.

ng-click="brandFnc($event)"$scope.brandFnc = function($event) {
    // 通过 $event.target 来获取
}
ev.target.parentElementev.target.parentElement.children[0].srcev.target.previousElementSiblingev.target.nodeNameconsole.log(ev.target.outerHTML);//<button ng-click="ngGetSrc($event)">获取src</button>---整个console.log(ev.target.innerHTML);//获取src--中间的内容原生js的方法:1)创建节点：createElement创建元素，
也可以使用createTextNode创建文本节点.
document.body指向的是<body>元素;document.documentElement则指向<html>元素
    //创建节点
    var createNode = document.createElement("p");

    var createTextNode = document.createTextNode("hello world");

    createNode.appendChild(createTextNode);

    document.body.appendChild(createNode);

    document.documentElement.appendChild(createNode);2)插入节点：appendChild，insertBefore，
insertBefore接收两个参数，第一个是插入的节点，第二个是参照节点，如insertBefore(a,b)，则a会插入在b的前面
//插入节点

 var createNode = document.createElement("p");var createTextNode = document.createTextNode("hello world");

  createNode.appendChild(createTextNode);

 var p1 = document.getElementById("p1");

 document.body.insertBefore(createNode,p1);3)替换和删除元素，从replaceChild和removeChild的字面意思看，就是删除子节点，因此调用者，需要包含子节点p1，不然调用会报错。返回的节点是替换的或删除的元素，被替换/删除的元素仍然存在，但document中已经没有他们的位置了。
//替换元素

var replaceChild = document.body.replaceChild(createNode,p1);//删除元素
var removeChild = document.body.removeChild(p1);4)节点的属性：firstChild:第一个子节点lastChild:最后一个子节点childNodes:子节点集合，获取其中子节点可以someNode.childNodes[index]或者someNode.childNodes.item(index)nextSibling:下一个兄弟节点
previousSibling：上一个兄弟节点
parentNode：父节点

<ul id="ul"><li>sdsssssss</li><li>qqqq</li><li>wwww</li><li>eeee</li></ul>

复制代码

   //节点属性

    var ul = document.getElementById("ul");

    var firstChild = ul.firstChild;

    console.log(firstChild.innerHTML);

    var lastChild = ul.lastChild;

    console.log(lastChild.innerHTML);

    var length = ul.childNodes.length;

    console.log(length);



    var secondChild = ul.childNodes.item(1);

    console.log(secondChild.innerHTML);



    var forthChild = ul.childNodes.item(2).nextSibling;

    console.log(forthChild.innerHTML);

    var thridChild = forthChild.previousSibling;

    console.log(thridChild.innerHTML);



    var parentNode = forthChild.parentNode;

    console.log(parentNode.innerHTML);5) 文档片段，好处在于减少dom的渲染次数，可以优化性能。

//文本片段

    var fragment = document.createDocumentFragment();

    var ul = document.getElementById("ul");

    var li = null;

    for (var i = 4; i >= 0; i--) {

        li = document.createElement("li");

        li.appendChild(document.createTextNode("item "+i));

        fragment.appendChild(li);

    }

    ul.appendChild(fragment);6）克隆元素
someNode.cloneNode(true):深度克隆，会复制节点及整个子节点
someNode.cloneNode(false):浅克隆，会复制节点，但不复制子节点 
//克隆

    var clone = ul.cloneNode(true);

    document.body.appendChild(clone);注意：1、childNodes.length存在跨浏览器的问题

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可以看到有关列表的html片段没有用 
<ul id="ul">
<li>sdsssssss</li>
<li>qqqq</li>
<li>wwww</li>
<li>eeee</li>
</ul>

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This writing format is written in a format without line breaks because in different browsers, the results of ul.childNodes.length are obtained. There are differences:
In ie, ul.childNodes.length does not calculate the newline spaces between li, so the value is 4. In ff, chrome, and safari, there will be 5 including the whitespace characters between li text node, so ul.childNodes.length is 9. To solve the cross-browser problem, you can remove the line breaks between li and change it to a one-line writing format.
2. CloneNode has cross-browser issues
In IE, elements copied through the cloneNode method will copy the event handler, for example, var b = a.cloneNode(true). If a has click, mouseover Wait for event monitoring, then b will also have these event monitoring.

In ff, chrome, and safari, the elements copied through the cloneNode method will only copy the attributes, and nothing else will be copied.
Therefore, to solve the cross-browser problem, it is best to copy the elements before copying. It's best to remove the event handler first.

Related recommendations:

Js process of operating DOM objects

Analysis of DOM operation examples in jQuery

How Js operates DOM and obtains browser height and width

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