查看window对象拥有的属性和方法
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
</head>
<body>
<script type="text/javascript">
document.body.style.textAlign = "center";
document.bgColor = "AliceBlue";
for (var i in window) {
document.write(i + "<br>");
}
</script>
</body>
</html>