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簡單的開關燈

??? 2019-02-10 00:11:32 242
????:<!DOCTYPE html> <html lang = "en"> <head>     <meta charset = "UTF-8">     <ti
<!DOCTYPE html>
<html lang = "en">
<head>
    <meta charset = "UTF-8">
    <title>JavaScript事件</title>
    <style>
        body {
            background: #333;
        }
        
        .box {
            width: 100px;
            margin: 200px auto 0;
            text-align: center;
            cursor: pointer;
        }
        
        .ball {
            width: 100px;
            height: 100px;
            background: rgba(255, 255, 255, 0.3);
            border-radius: 50%;
            box-shadow: 0 0 20px #111;
        }
        
        p {
            margin-top: 50px;
            color: rgba(255, 255, 255, 0.5);
            text-shadow: 0 6px 3px #999;
        }
    
    </style>
</head>
<body>
<div class = "box">
    <div class = "ball"></div>
    <p>點擊開燈</p>
</div>
</body>
<script src = "https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js"></script>
<script>
    var body = document.getElementsByTagName('body')[0];
    var box = document.getElementsByClassName('box')[0];
    var ball = document.getElementsByClassName('ball')[0];
    var text = document.getElementsByTagName('p')[0];
    box.onclick = function () {
        if (body.style.backgroundColor != 'rgb(238, 238, 238)') {
            body.style.backgroundColor = 'rgb(238, 238, 238)';
            ball.style.boxShadow = '0 0 100px yellow';
            text.innerText = '點擊關燈';
            text.style.color = '#999';
        } else {
            body.style.backgroundColor = '#333';
            // 請問老師:下面為什么打印出來是 rgb(51, 51, 51) ,不是 #333 ?
            // console.log(body.style.backgroundColor);
            ball.style.boxShadow = '0 0 20px #111';
            console.log(text);
            text.innerText = '點擊開燈';
            text.style.color = 'rgba(255, 255, 255, 0.5)';
        }
    }

    /*
    常用事件
    下面是一個屬性列表,這些屬性可以插入HTML標簽來定義事件動作
    屬性                             描述
    onload                         一張頁面或一幅圖像完成加載
    
    onfocus                       元素獲得焦點
    onblur                         元素失去焦點
    onchange                    域的內容被改變
    onsubmit                     確認按鈕被點擊
    
    onclick                         點擊時
    ondblclick                    雙擊時
    
    onkeydown                  某個鍵盤按鍵被按下
    onkeyup                       某個鍵盤按鍵被松開
    onkeypress                   某個鍵盤按鍵被按下并松開
    
    onmousedown             鼠標按鈕被按下
    onmouseup                  鼠標按鍵被松開
    onmousemove             鼠標被移動
    onmouseover               鼠標移動到某元素之上
    onmouseout                鼠標從某元素移開
    */
</script>
</html>


?? ???:韋小寶?? ??:2019-02-11 10:27:06
???? ??:你把前面的backgroundColor也都改成不是rgb的形式你再看看!

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