SOURCE

console 命令行工具 X clear 

                    

                        
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console

            
window.onload=function(){

    //找到父元素
    var oTds = document.getElementsByTagName("td");

    for(var i=0;i<oTds.length;++i){
        oTds[i].onclick=function(){
            var oParent=this .parentNode;
            oParent.style.color="white";
            oParent.style.backgroungColor="lightskyblue";
        }
    }

    //找到子元素节点和子元素

    var oUl = document.getElementById("list");
    var oChildElements = oUl.children;
    var oChildNodes = oUl.childNodes;
    console.log("Line19:"+oChildElements.length);
    console.log("line20:"+oChildNodes.length);

    var oBtn = document.getElementById("btn");

    oBtn.onclick = function(){
        //删除最后一个子节点
       // oUl.removeChild(oUl.lastChild);

       //删除元素节点
       /*if(oUl.lastChild.nodeType ==3){
           oUl.removeChild(oUl.lastChild);
           oUl.removeChild(oUl.lastChild);
       }
       else{
           oUl.removeChild(oUl.lastChild);
       }*/
       oUl.removeChild
    }
}

            
<!DOCTYPE html> 
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <style type="text/css">
        
    </style>
    <script>
       
    </script>
</head>
<body>
    <table>
        <caption>考试成绩表</caption>
        <tr>
            <td>小明</td>
            <td>80</td>
            <td>80</td>
            <td>80</td>
        </tr>
        <tr>
            <td>小红</td>
            <td>90</td>
            <td>90</td>
            <td>90</td>
        </tr>
        <tr>
            <td>小杰</td>
            <td>100</td>
            <td>100</td>
            <td>100</td>
        </tr>
    </table>

    <ul id="list">
        <li>HTML</li>
        <li>CSS</li>
        <li>JavaScript</li>
        <li>jQuery</li>
        <li>Vue.js</li>
    </ul>
    <button id="btn">删除</button>
</body>
</html>

            
table{
    border-collapse:collapse;
}
table,tr,td{
    border:1px solid gray;
}