我正在使用PHP开发我的第一个简单网站.现在,我正在管理页面中工作,我想让他添加,删除用户和编辑现有用户的个人信息.我做了添加和删除.现在,我想开发编辑用户.首先,我希望他从下拉列表中选择用户,然后在从下拉列表中选择用户信息后自动获取用户信息,然后编辑他的信息.那我该怎么办呢？

我的代码：

PHP
ob_start();
$host="localhost"; // Host name
$username="root"; // MysqL username
$password="13524"; // MysqL password
$db_name="sharingi_db"; // Database name

// Connect to server and select databse.
MysqL_connect("$host","$username","$password")or die("cannot connect");
MysqL_select_db("$db_name")or die("cannot select DB");

?>

PHP
           if(isset($_GET['username']))
           echo "{$_GET['username']}"; 
           else echo "Select one";
        ?> 
            PHP
                   if(isset($_GET['username'])){
           $exceptcc = $_GET['username'];
           $sql = "SELECT username FROM user WHERE user.username NOT IN
                                 ('$exceptcc')";
                    }
           else 
           $sql = "SELECT username FROM user";
           $result = MysqL_query($sql);
           while($row = MysqL_fetch_array($result)){
           echo "PHP 
           $thecc = $_GET['username'];
           $sql = "SELECT Firstname FROM user WHERE Username=$thecc";
           $result = MysqL_query($sql);
           while($row = MysqL_fetch_array($result)){
           echo "{$row['Firstname']}>{$row['Firstname']}}";
                                }
        ?>