HTML5 body设置全屏背景图片的示例代码

html,body{
	width:100%;
	height:100%
}

body{
  font-family: "华文细黑";
  background:url("../img/Flyer-bg.png") no-repeat;
  background-size: 100%;
}

<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width,minimum-scale=1.0">
    <title>缓存</title>
    <script src="js/jquery-1.8.2.min.js"></script>
    <script src="js/store.min.js"></script>
    <style>
        .parent{
            width:200px;
            height: 200px;
            /* 以下属性垂直居中 */
            position: absolute;
            top: 0;
            bottom: 0;
            left: 0;
            right: 0;
            margin: auto;
            background-color: #aaa;
        }
    </style>
</head>
<body>
    <div class="parent">111</div>
</body>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <div id="Layer1" style="position:fixed; left:0px; top:0px; width:100%; height:100%">  
    <img src="https://zhanzhang.eapis.site/public/uploads/images/20251022/31_202510220843403025.jpg"; width="100%" height="100%"/>  
</body>
</html>

.float-left {
    float: left;
}
.float-right {
    float: right;
}
.clear-fix:after {
    display: table;
    content: '';
    clear: both;
}