試一試 - CSS background-image

<!DOCTYPE html>
<html>
<head>
<style>
body {
 background-image: url("img_tree.png");
 background-repeat: no-repeat;
 background-position: right top;
 margin-right: 200px;
 background-attachment: fixed;
}
</style>
</head>
<body>

<h1>Hello World!</h1>
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
The background-image is fixed. Try to scroll down the page.
If you do not see any scrollbars, try to resize the browser window.

</body>
</html>