DOM元素节点查找练习

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">    
    <title>IFE ECMAScript</title>
</head>
<body>        
    <div id="wrapper">
        <div id="news-top" class="section">
            <h3>Some title</h3>
            <div class="content">
                <ul>
                    <li><span>HTML</span><a href="">Some Link1</a></li>
                    <li><span>JS</span><a class="active" href="">Some Link2</a></li>
                    <li><span>CSS</span><a href="">Some Link3</a></li>
                    <li><span>JS</span><a href="">Some Link4</a></li>
                </ul>
            </div>
            <img src="">
            <p class="">Some Text</p>
        </div>
        <div id="news-normal" class="section">
            <h3>Some title</h3>
            <div class="content">
                <ul>
                    <li><span>HTML</span><a href="">Some Link1</a></li>
                    <li><span>HTML</span><a href="">Some Link2</a></li>
                    <li><span>JS</span><a class="active" href="#">Some Link3</a></li>
                    <li><span>CSS</span><a href="">Some Link4</a></li>
                </ul>
            </div>
            <img src="">
            <p class="">Some Text</p>
        </div>      
    </div>
    <script>

    function getAllListItem() {
        // 返回页面中所有li标签
        console.log(document.getElementsByTagName("li"));
    }

    function findAllHtmlSpanInOneSection(sectionId) {
        // 返回某个section下所有span中内容为HTML的span标签
        var spanlist = document.getElementById(sectionId).getElementsByTagName("span");
        for (var i = 0 ; i < spanlist.length; i++) {
            if (spanlist[i].innerHTML == "HTML") {
                console.log(spanlist[i]);
            }
        }
    }

    function findListItem(sectionId, spanCont) {
        // 返回某个section下，所有所包含span内容为spanCont的LI标签
        var lilist = document.getElementById(sectionId).getElementsByTagName("li");
        var arr = [];
        for (var i = 0; i < lilist.length; i++) {
            if (lilist[i].getElementsByTagName("span")[0].innerHTML == spanCont) {
                arr.push(lilist[i]);
            }
        }
        for (var i = 0; i < arr.length; i++) {
            console.log(arr[i]);
        }
    }

    function getActiveLinkContent(sectionId) {
        // 返回某个section下，class为active的链接中包含的文字内容
        var alist = document.getElementById(sectionId).getElementsByTagName("a");
        for (var i = 0 ; i < alist.length; i++) {
            if (alist[i].getAttribute("class") == "active") {
                console.log(alist[i].innerHTML);
            }
        }
    }

    getAllListItem();
    findAllHtmlSpanInOneSection("wrapper");
    findListItem("wrapper", "JS");
    getActiveLinkContent("wrapper");

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

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">    
    <title>IFE ECMAScript</title>
</head>
<body>        
    <div id="wrapper">
        <div id="news-top" class="section">
            <h3>Some title</h3>
            <div class="content">
                <ul>
                    <li><span>HTML</span><a href="">Some Link1</a></li>
                    <li><span>JS</span><a class="active" href="">Some Link2</a></li>
                    <li><span>CSS</span><a href="">Some Link3</a></li>
                    <li><span>JS</span><a href="">Some Link4</a></li>
                </ul>
            </div>
            <img src="">
            <p class="">Some Text</p>
        </div>
        <div id="news-normal" class="section">
            <h3>Some title</h3>
            <div class="content">
                <ul>
                    <li><span>HTML</span><a href="">Some Link1</a></li>
                    <li><span>HTML</span><a href="">Some Link2</a></li>
                    <li><span>JS</span><a class="active" href="#">Some Link3</a></li>
                    <li><span>CSS</span><a href="">Some Link4</a></li>
                </ul>
            </div>
            <img src="">
            <p class="">Some Text</p>
        </div>      
    </div>
    <script>

    function getAllListItem() {
        // 返回页面中所有li标签
        console.log(document.querySelectorAll("li"));
    }

    function findAllHtmlSpanInOneSection(sectionId) {
        // 返回某个section下所有span中内容为HTML的span标签
        var sec = document.querySelector(sectionId);
        var spanlist = sec.querySelectorAll("span");
        for (var i = 0 ; i < spanlist.length; i++) {
            if (spanlist[i].innerHTML == "HTML") {
                console.log(spanlist[i]);
            }
        }
    }

    function findListItem(sectionId, spanCont) {
        // 返回某个section下，所有所包含span内容为spanCont的LI标签
        var lilist = document.querySelectorAll(sectionId + " " + "li" + " " + "span");
        var arr = [];
        for (var i = 0; i < lilist.length; i++) {
            if (lilist[i].innerHTML == spanCont) {
                arr.push(lilist[i]);
            }
        }
        for (var i = 0; i < arr.length; i++) {
            console.log(arr[i]);
        }
    }

    function getActiveLinkContent(sectionId) {
        // 返回某个section下，class为active的链接中包含的文字内容
        var alist = document.querySelectorAll(sectionId + " " + "a");
        for (var i = 0 ; i < alist.length; i++) {
            if (alist[i].getAttribute("class") == "active") {
                console.log(alist[i].innerHTML);
            }
        }
    }

    getAllListItem();
    findAllHtmlSpanInOneSection("#wrapper");
    findListItem("#wrapper", "JS");
    getActiveLinkContent("#wrapper");

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

DOM元素节点查找练习

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