console 命令行工具 X clear

console

<!DOCTYPE html>
<!-- CSS_box_model001.html -->
<html>
<head>
    <style>
        #firstp {
            border-width: 2px;
            border-style: solid;
        }
    </style>
</head>
<body>
    <p id="firstp"> First paragraph with border <p>
    <p> secondp paragraph with no border </p>
</body>
</html>