javascript中DOM獲取和設置元素的內容、樣式及效果

時間 2020-02-06

標籤 javascript dom 獲取設置元素內容樣式效果欄目 JavaScript 简体版

原文原文鏈接

getElementById() 根據id獲取dom元素css

沒有找到則返會Nullhtml

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <div id="box"></div>
    <script>
        var box=document.getElementById("box");
        console.log(box);//<div id="box"></div>

        var boxs=document.getElementById("boxs");
        console.log(boxs);//null
    </script>
</body>
</html>

在不一樣的範圍內查找dom元素數組

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <ul id="list">
        <li>li</li>
        <li>li</li>
        <li>li</li>
        <li>li</li>
        <li>li</li>
    </ul>
    <ol>
        <li>li</li>
        <li>li</li>
    </ol>
    <script>
        var ul=document.getElementById("list");
        var lis1=ul.getElementsByTagName("li");
        console.log(lis1.length);//5

        var lis2=document.getElementsByTagName("li");
        console.log(lis2.length);//7
    </script>
</body>
</html>

設置元素的css樣式dom

ele.style.屬性=屬性值spa

若是是連字符形式的，須要轉換爲駝峯形式code

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <ul id="list">
        <li>li</li>
        <li>li</li>
        <li>li</li>
        <li>li</li>
        <li>li</li>
    </ul>
    <ol id="list2">
        <li>li</li>
        <li>li</li>
    </ol>
    <script>
        var ul=document.getElementById("list");
        ul.style.color="red";

        var ol=document.getElementById("list2");
        ol.style.fontWeight="bold";

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

設置數組元素的樣式htm

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <ul id="list">
        <li>li</li>
        <li>li</li>
        <li>li</li>
        <li>li</li>
        <li>li</li>
    </ul>
    <ol id="list2">
        <li>li</li>
        <li>li</li>
    </ol>
    <script>
        var ul=document.getElementById("list");
        ul.style.color="red";

        var ol=document.getElementById("list2");
        var lis=ol.getElementsByTagName("li");
        lis[0].style.backgroundColor="pink";
        lis[1].style.backgroundColor="#abcdef";

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

innerHTML 獲取和設置元素的內容，包括html標籤和文本blog

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <ol id="list2">
        <li>咪咪</li>
        <li>灰灰</li>
    </ol>
    <script>
        var ol=document.getElementById("list2");
        var lis=ol.getElementsByTagName("li");
        for(var i=0,len=lis.length;i<len;i++){
            lis[i].innerHTML+='~~~';
            console.log(lis[i].innerHTML);
        }

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

className 設置和獲取元素的類ip

設置的類會把原來的類替換掉rem

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        .orange{color:orange;}
    </style>
</head>
<body>
    <ol id="list2">
        <li>咪咪</li>
        <li>灰灰</li>
    </ol>
    <script>
        var ol=document.getElementById("list2");
        var lis=ol.getElementsByTagName("li");
        lis[0].className="orange";
        console.log(lis[0].className);

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

getAttribute() 獲取屬性

自定義屬性建議都以 data- 開頭

ele.屬性名直接獲取屬性（標籤自帶屬性，除了class爲className)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        .orange{color:orange;}
    </style>
</head>
<body>
    <p id="p" class="pp" data-type="title"></p>
    <input id="text" type="text" name="text" value="hh" validate="true">
    <script>
        var p=document.getElementById("p");
        console.log(p.id);//p
        console.log(p.className);//pp
        console.log(p.getAttribute("data-type"));//title

        var text=document.getElementById("text");
        console.log(text.type);//text
        console.log(text.name);//text
        console.log(text.value);//hh
        console.log(text.getAttribute("validate"));//true

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

setAttribute() removeAttribute() 給dom元素設置和刪除屬性

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        .orange{color:orange;}
    </style>
</head>
<body>
    <p id="p" class="pp" data-type="title"></p>
    <script>
        var p=document.getElementById("p");
        p.setAttribute("data-color","orange");
        console.log(p.getAttribute("data-color"));//orange
        
        p.removeAttribute("data-color");
        console.log(p.getAttribute("data-color"));//null


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