CSS 背景
DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>title>
<link rel="stylesheet" type="text/css" href="css_back.css"/>
head>
<body>
<div id="div1">
this is a text
div>
body>
html>
body{ /* 默认水平垂直都重复 */ background-image: url(img.jpg); /* 仅在水平重复 */ background-repeat: repeat-x; background-position: bottom; /* 固定fixed 还是随页面滚动 scroll */ background-attachment: fixed; } #div1{ background-color: green; opacity: 0.5;/*透明度*/ background: rgba(0, 128, 0, 0.3) /*背景色透明*/ }