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javascript基础--DOM选取子节点

一、节点选取

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <script>
        // 首尾子节点有兼容性问题
        // firstChild           firstElementChild
        // lastChild            lastElementChild
        // 兄弟节点
        // nextSlibing          nextElementChild
        // previousSibling      previousElementsSibling
        window.onload = function() {
            var oLi = document.getElementById(‘li1‘);
            var oPre = oLi.previousElementSibling || oLi.previousSibling;
            oPre.style.background = "red";
        }
    </script>
</head>

<body>
    <ul id="ul1">
        <li></li>
        <li id="li1"></li>
        <li></li>
    </ul>
</body>

</html>

 二、dom节点childNodes和nodeType

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <script>
        window.onload = function() {
            var oUl = document.getElementById(‘ul1‘);
            // alert(oUl.childNodes[1].nodeType);
            var i = 0;
            for (i = 0; i < oUl.childNodes.length; i++) {
                if (oUl.childNodes[i].nodeType == 1) { //1是指标签节点  3是指文本节点
                    oUl.childNodes[i].style.background = ‘red‘;
                }
            }
        }
    </script>
</head>

<body>
    <ul id="ul1">
        <li>111</li>
        <li>222</li>
        <li>333</li>
    </ul>
</body>

</html>

 三、children是没有兼容问题的childNodes

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <script>
        window.onload = function() {
            var oUl = document.getElementById(‘ul1‘);
            // alert(oUl.children.length);
            var i = 0;
            for (i = 0; i < oUl.children.length; i++) {
                oUl.children[i].style.background = ‘red‘;
            }
        }
    </script>
</head>

<body>
    <ul id="ul1">
        <li>111</li>
        <li>222</li>
        <li>333</li>
    </ul>
</body>

</html>

 

javascript基础--DOM选取子节点