现在直接用 selected就可以的
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>下拉列表框</title>
</head>
<body>
<form action="save.php" method="post" >
<label>爱好:</label>
<select>
<optgroup label="爱好">
<option value="看书" selected>看书</option>
<option value="旅游">旅游</option>
<option value="运动">运动</option>
<option value="购物">购物</option>
</optgroup>
</select>
</form>
</body>
</html>
