SOURCE

window.onload = function() {
    // document.getElementById
    var oDiv1 = document.getElementById("Div1");
    console.log("The nodeType of oDiv1 is " + oDiv1.nodeType);
    console.log("There are " + oDiv1.childNodes.length + " child nodes in oDiv1");
    console.log("The nodeType of the first child node of oDiv1 is " + oDiv1.childNodes[0].nodeType);
    console.log("The nodeValue of the first child node of oDiv1 is " + oDiv1.childNodes[0].nodeValue);
    console.log("The nodeType of the second child node of oDiv1 is " + oDiv1.childNodes[1].nodeType);
    console.log("The tagName of the second child node of oDiv1 is " + oDiv1.childNodes[1].tagName);
    console.log("The nodeType of the third child node of oDiv1 is " + oDiv1.childNodes[2].nodeType);
    console.log("The nodeValue of the third child node of oDiv1 is " + oDiv1.childNodes[2].nodeValue);

    console.log("There are " + oDiv1.attributes.length + " attributes in oDiv1");
    console.log("The name of attribute of oDiv1 is " + oDiv1.attributes[0].name);
    console.log("The nodeType of attribue of oDiv1 " + oDiv1.attributes[0].nodeType);

    // getElementsByTagName
    var oUls = document.getElementsByTagName("ul");
    console.log("There are " + oUls.length + " ul in document." );

    var oList1Lis = oUls[0].getElementsByTagName("li");
    console.log("There are " + oList1Lis.length + " li in the first ul." );

    var oDocLis = document.getElementsByTagName("li");
    console.log("There are " + oDocLis.length + " li in the document." );

    // getElementsByClassName
    var oRadios = document.getElementsByClassName("radio");
    console.log("There are " + oRadios.length + " radio class in the document." );

    var oDivs = document.getElementsByTagName("div");
    var oRadios1 = oDivs[1].getElementsByClassName("radio");
    console.log("There are " + oRadios1.length + " radio class in the second div." );

    // querySelector
    // 使用id选择器去找到第一个值为id名的元素节点, 这种情况，尽量用getElementById，效率更高
    var oList1 = document.querySelector("#List1");
    console.log("Line 38: " + oList1.id);

    // 使用元素选择器去找到所有的ul元素下的li子元素
    var oLis = document.querySelectorAll("ul li");
    console.log("Line 42: " + oLis.length);
    oLis[0].style.color = "red";
    oLis[1].style.color = "blue";
    oLis[2].style.color = "green";

    // 使用类选择器找到所有class为radio的元素, 这种情况，尽量用getElementByClassName，效率更高
    var oClassRadios = document.querySelectorAll(".radio");
    console.log("Line 49: " + oClassRadios.length);

    // 使用选择器查找第一个class为radio的div元素
    var oClassRadioDiv = document.querySelector("div.radio");
    console.log("Line 53: " + oClassRadioDiv.tagName);

    // 使用选择器查找第一个class为radio的div元素下所有calss为radio的子元素
    var oClassDivRadios = oClassRadioDiv.querySelectorAll(".radio");
    console.log("Line 57: " + oClassDivRadios.length);

    // 使用伪类选择器找到第一个checked状态为真的input
    var oCheckedInput = document.querySelector("input:checked");
    console.log("Line 61: " + oCheckedInput.value);
    
    // 使用元素选择器找到所有的ul元素，这种情况，尽量使用getElementByTagName，效率更高
    var oLists = document.querySelectorAll("ul");
    console.log("Line 65: " + oLists.length);

    // getElementsByName
    var oFruitInputs = document.getElementsByName("fruit");
    console.log("Line 69: " + oFruitInputs[0].value)

    //var oGenderInputs = oClassRadioDiv.getElementsByName("gender");
    //console.log("Line 66: " + oGenderInputs[0].value)


    // document.title
    console.log("Line 76: " + document.title);
    

    // document.body
    console.log("Line 80: " + document.body.tagName);

    // 创建一个简单的button,把它插入到文档的末尾
    var oButton = document.createElement("button");
    var oTextNode = document.createTextNode("替换");
    oButton.appendChild(oTextNode);

    //document.body.appendChild(oButton);

    document.body.insertBefore(oButton, oDivs[1]);

    // replaceChild
    
    oButton.onclick = function() {
        // 元素替换
        var oDiv1 = document.getElementById("Div1");
        var oPHi = document.createElement("p");
        var oPText = document.createTextNode("Hi");
        oPHi.appendChild(oPText);

        oDiv1.replaceChild(oPHi, oDiv1.childNodes[1]);

    }

    // 查看属性
    console.log("Line 103: The id of oDiv1: " + oDiv1.id);
    console.log("Line 104: The data of oDiv1: " + oDiv1.getAttribute("id"));
    console.log("Line 105: The data of oDiv1: " + oDiv1.data); // 不能通过对象属性获取自定义属性的值
    console.log("Line 106: The data of oDiv1: " + oDiv1.getAttribute("data"));

    // 设置属性
     var oInsertInput = document.getElementById("insertInput");
     //oInput.value = "Enter";
     oInsertInput.setAttribute("value", "Enter...");


    // 判断属性是否存在
    if (oInsertInput.hasAttribute("value")) {
        console.log("Line 113: The value of InsertInput: " + oInsertInput.getAttribute("value"));
    }
    
    // 删除属性
    oInsertInput.removeAttribute("value");
    55
    if (oInsertInput.hasAttribute("value")) {
        console.log("Line 119: The value of InsertInput: " + oInsertInput.getAttribute("value"));
    }
    
    oDiv1.removeAttribute("class");
    oDiv1.setAttribute("class","div1");
}

function insertToList() {
    var oInput = document.getElementById("insertInput");
    var strValue = oInput.value;

    //1. 创建节点的方法

    //2. 克隆节点的方法
    var oList1 = document.getElementById("List1");
    var oLis = oList1.getElementsByTagName("li");
    var oCreatedLi = oLis[1].cloneNode(true);
    oCreatedLi.textContent = strValue;

    oList1.insertBefore(oCreatedLi, oLis[0]);
}

function appendToList() {
    var oInput = document.getElementById("appendInput");
    var strValue = oInput.value;

    //1. 创建节点的方法

    //2. 克隆节点的方法
    var oList2 = document.getElementById("List2");
    var oLis = oList2.getElementsByTagName("li");
    var oCreatedLi = oLis[1].cloneNode(true);
    oCreatedLi.textContent = strValue;

    oList2.appendChild(oCreatedLi);
}

function removeBottom() {
    var oList2 = document.getElementById("List2");
    var oLis = oList2.getElementsByTagName("li");

    oList2.removeChild(oLis[oLis.length - 1]);
}

<!DOCTYPE html> 
<html>
    <head>
        <meta charset="utf-8" />
        <title></title>
        <style>
            #Div1 {
                color : red;
            }
        </style>
    </head>
    <body>
        <div id="Div1" data="自定义属性" class="divi">
            <p id="Paragraph">Hello</p>
            World
        </div>
        <div>
            <ul id="List1" class="list">
                <li id = "11"> Html </li>
                <li> Javascript </li>
                <li> CSS </li>
                <li> Webpack </li>
            </ul>
            <input id="insertInput" type="text"></input>
            <button onclick="insertToList()">插入列表元素顶部</button>
            <button onclick="removeTop()">删除顶部元素</button>
        </div>
        <div>
            <ul id="List2" class="list">
                <li> Vue </li>
                <li> React </li>
                <li> Angular </li>
            </ul>
            <input id="appendInput" type="text"></input>
            <button onclick="appendToList()">添加到列表元素的尾部</button>
            <button onclick="removeBottom()">删除尾部元素</button>
        </div>
        <div class="radio">
            你的性别是：
            <input class="radio" type="radio" name="gender" checked="true" value="女">女</input>
            <input class="radio" type="radio" name="gender" value="男">男</input>
        </div>
        <div>
            你喜欢那些水果：
            <input class="radio" type="checkbox" name="fruit" checked="true" value="苹果">苹果</input>
            <input type="checkbox" name="fruit" value="梨">梨</input>
        </div>    
        <div id="DynamicDiv1"></div>
        <div id="DynamicDiv2"></div>
    </body>
</html>

.list {
    background-color: lightblue;
}

.div1 {
    background-color: lavender;
}