PHP代码在提交之前执行

Question

我制作了一个登录表单，但还有很多其他问题，现在我发现在提交 Submit 之前已执行了PHP代码。 该如何解决？ 由于PHP不支持onclick事件（反正很烂！），所以我看不到任何已知的解决方案！

码：

//Get the form with POST
$user = mysql_real_escape_string($_POST['user']);
$password = mysql_real_escape_string($_POST['pass']);



$usernames=mysql_query("SELECT * FROM user_info WHERE Username='" . $_POST['user'] . "' AND Password='" . $_POST['pass'] . "'");
if(!$usernames){echo mysql_error();}

$count=mysql_num_rows($usernames);
if(!$count){echo mysql_error();}

//If $count is equal to one, register the user and redirect him to his page, or else   echo him that his info is wrong
if($count === 1) {
$_SESSION['code'] = "titan";
$_SESSION['ande'] = $user;
$_SESSION['password'] = $password;
header("location: home.php");}
else {
echo "<p style='color:red;text-align:center;'>Wrong username or password!</p>";}

Answer 1

将应该在表单提交后执行的代码包装在IF语句中，该语句检查是否提交了表单：

if ('POST' === $_SERVER['REQUEST_METHOD'])
{
    // your code goes here
}

Answer 2

检查表格是否提交

if(isset($_POST['user'])) {

   //Your php code goes here

}

---

根据您的评论，我扩展了此答案

只需将所有代码置于您在问题中发送的这种情况下

if(isset($_POST['user']))
{

    //Get the form with POST
    $user = mysql_real_escape_string($_POST['user']);
    $password = mysql_real_escape_string($_POST['pass']);



    $usernames=mysql_query("SELECT * FROM user_info WHERE Username='" . $_POST['user'] . "' AND Password='" . $_POST['pass'] . "'");
    if(!$usernames){echo mysql_error();}

    $count=mysql_num_rows($usernames);
    if(!$count){echo mysql_error();}

    //If $count is equal to one, register the user and redirect him to his page, or else   echo him that his info is wrong
    if($count === 1) {
    $_SESSION['code'] = "titan";
    $_SESSION['ande'] = $user;
    $_SESSION['password'] = $password;
    header("location: home.php");}
    else {
    echo "<p style='color:red;text-align:center;'>Wrong username or password!</p>";}

}

Answer 3

我没有告诉你的是，PHP代码与HTML表单和其余HTML文件在同一个文件中...我试图用AJAX重新制作代码，（（==无效，但还是有帮助！ ），为此，我将PHP代码移到了另一个文件（ Login_engine.php ）中，就是这样！当然，仍然存在一个小问题：现在，红色文本显示在Login_engine.php ... Login_engine.php ！