為什么這個類沒有效果？把類換成“div”卻可以
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>練習2</title>
<style type="text/css">
.ba:before {
? ?content: "今天";
}
</style>
</head>
<body>
<div class=".ba">中午吃什么呢？</div>
</body>
</html>
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<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>練習2</title>
<style type="text/css">
.ba:before {
? ?content: "今天";
}
</style>
</head>
<body>
<div class=".ba">中午吃什么呢？</div>
</body>
</html>
2021-03-16
舉報
2021-03-17
<!DOCTYPE?html>
<html?lang="en">
??<head>
????<meta?charset="UTF-8"?/>
????<meta?http-equiv="X-UA-Compatible"?content="IE=edge"?/>
????<meta?name="viewport"?content="width=device-width,?initial-scale=1.0"?/>
????<title>Document</title>
????<style>
??????.cc:before?{
????????content:?"今天";
??????}
????</style>
??</head>
??<body>
????<div?class="cc">吃什么呢</div>
??</body>
</html>
2021-03-16
也不能放圖片