<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>
body {
background-image: url('../jQueryLibrary/img/11.jpg');
/* 背景图 写在下面的把上面的覆盖掉了 */
background-image: url('../jQueryLibrary/img/3.jpg');
/* 需要调整图片的大小，到合适尺寸就可以了 */
background-image: url('../jQueryLibrary/img/sky.jpg');
/* 城市背景 */
/* background-image: url('../jQueryLibrary/img/city.jpg'); */
/* 居中对齐
text-align: center; */
background-color: #cccccc;
}
</style>
</head>
<body>
<h1>hello world</h1>
<h1>你好 上海</h1>
<h2>你好 济南</h2>
</body>
效果