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Node operation examples in JS

小云云Original: 2018-03-26 16:16:411375browse

This article mainly shares with you examples of node operations in JS, mainly in the form of code, hoping to help everyone.

Node addition, deletion and modification query

<!DOCTYPE html><html lang="en"><head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .p1,.p2,.p3,.p4{            width: 300px;            height: 100px;        }
        .p1{            background-color: green;        }
         .p2{            background-color: yellow;        }
         .p3{            background-color: rebeccapurple;        }
         .p4{            background-color: deeppink;        }
    </style></head><body><p class="p1">
    <button onclick="add()">add</button>
    hello p1</p><p class="p2">
    <button onclick="del()">del</button>
    hello p2</p><p class="p3">
    <button onclick="change()">change</button>
    <p>hello p3</p></p><p class="p4">hello p4</p><script>###############增加节点######################    function change() {
        var img=document.createElement("img");//<img src="">
        //img.setAttribute("src","meinv.jpg");
        img.src="meinv.jpg";        var ele=document.getElementsByTagName("p")[0];        var father=document.getElementsByClassName("p3")[0];

        father.replaceChild(img,ele)


    }
    ###############修改节点######################    function add() {
        var ele=document.createElement("p");//<p></p>
        ele.innerHTML="<h1>hello p</h1>";        //ele.innerText="<h1>hello p</h1>";
        ele.style.color="red";
        ele.style.fontSize="10px";        var father=document.getElementsByClassName("p1")[0];
        father.appendChild(ele)

    }
###############删除节点######################    function del() {
        var father=document.getElementsByClassName("p1")[0];        var son=father.getElementsByTagName("p")[0];
        father.removeChild(son)
    }</script></body></html>

Two ways to use JS to bind events

<!DOCTYPE html><html lang="en"><head>
    <meta charset="UTF-8">
    <title>Title</title></head><body><p onclick="func(this)">hello</p><p>hello p</p><script>
    // 绑定事件方式一
    function func(self) {
        console.log(self)
        alert(1234)
    }    // 绑定事件方式二
    var ele=document.getElementsByTagName("p")[0]
    ele.onclick=function () {
        console.log(ele);
        console.log(this);//        alert(6666)


    }</script></body></html>

JS class attribute

<script>
    var ele=document.getElementsByTagName("p")[0];
      # class的名称
    console.log(ele.className);
          # 以列表返回class中值
    console.log(ele.classList[0]);
          # 以列表返回class中值
    console.log(ele.classList[1]);
    #  向列表中增加元素
    ele.classList.add("hide")
    console.log(ele.className);</script>

Event object: encapsulated Event information
can be used to prevent event propagation

<!DOCTYPE html><html lang="en"><head>
    <meta charset="UTF-8">
    <title>Title</title></head><body><form action="" id="form1">
    <input type="text" name="username">
    <input type="submit" value="提交"></form><script>
    var ele=document.getElementById("form1");
    ele.onsubmit=function (e) {//        console.log("hello")
        alert(1234);        // 方式一  返回false
         return false
        // 方式二  preventDefault函数
        //e.preventDefault()
    }</script></body></html>

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