PHP 中的定义函数 "mysql_entities_fix_string" 未被调用

The Defined function "mysql_entities_fix_string" in PHP isn't getting called

<?php
require_once 'login.php';
require_once 'welcome.php';
$db_server = mysql_connect($db_hostname,$db_username,$db_password);
if(!$db_server) die("Unable to connect with MySql : " . mysql_error());

mysql_select_db($db_database) or die("Unable to connect with db");


echo <<<_END
<form action = 'ps.php' method = 'post'><pre>
Enter your Username <input type = 'text' name = 'username'>
Enter your Password <input type = 'text' name = 'password'>
<input type = 'submit' value = 'Cl1ck M3'>
</pre></form>
_END;

if (isset($_POST['username']) && isset($_POST['password']))
{
    //echo "Fine till here1";
    echo $_POST['username']."  Without htmlentities <br>";
    $usernameP = mysql_entities_fix_string($_POST['username']);
    if (!$usernameP) die ("No value fetched in the variable usernameP");

    $passwordP = mysql_entities_fix_string($_POST['password']);
    if (!$passwordP) die ("No value fetched in the variable passwordP");

    $query = "SELECT * FROM hacker WHERE username = '$usernameP' AND password = '$passwordP'";
    $result = mysql_query($query,$db_server);
    if(!$result) die ("Unable to execute query : " . mysql_error());

    $rows = mysql_num_rows($result);

        $row = mysql_fetch_row($result);
        echo $row[0];
        if ($row[0] == '$username' && $row[1] == '$passwordP')
        {
            echo "Credentials Authorized";
        }

   function mysql_entities_fix_string($string)
         {
                return htmlentities(mysql_fix_string($string));
        }   

    function mysql_fix_string($string)
        {
                if (get_magic_quotes_gpc()) $string = stripslashes($string);
                return mysql_real_escape_string($string);
         }
    }   
mysql_close($db_server);

?>

我正在尝试测试一个简单的 PHP 页面。我正在使用函数 "mysql_entities_fix_string" 过滤掉恶意输入,但程序无法调用它。因此在 $usernameP 或 $passwordP 中没有获取任何值。 任何人都可以提出建议吗?

您正在有条件地定义函数。如果定义了函数,例如在 if 语句中,它仅在 之后 您的代码对其执行后才可用。相反,在主作用域 ("outside all the brackets") 中定义的函数是在文件的其余部分 运行.

之前定义的