PHP警报消息

Question

I know the first thing everyone is going to say is that this has been posted hundreds of times; however, I have tried all the different methods people have suggested with still no luck... I am trying to get an alert message to popup if the login fails but for some reason the message does not want to appear. Here's what I have so far:

if($conn) {
    $result=sqlsrv_query($conn, "SELECT * FROM Operator
    WHERE Username='{$_POST['login']}'");
    $pass=sqlsrv_fetch_array($result);
    if($pass["Password"] === $_POST['password']) {
        session_start();
        $_SESSION['loggedin']=true;
        header("Location: home.php");
        exit;
    }
    else {
        header("Location: login.php");
        echo '<script type="text/javascript">';
        echo 'alert("Password Invalid!")';
        echo '</script>';
    }
}
sqlsrv_close($conn);

The php is working fine but for some reason I can't get the javascript to work. Any ideas?

Answer 1

i think, the problem is here. you are redirecting the page before the alert message

header("Location: login.php"); /* Redirect browser */

try removing it, or make it redirect after a couple of seconds, like this

header( "refresh:5;url=login.php" ); //redirect after 5 seconds

or you prompt a dialog for the user to click to go to next page. remove the header() tho

<script type="text/javascript">
<!--
   var retVal = confirm("Login FAILED! Do you want to continue ?");
   if( retVal == true ){
      window.location.href = "login.php";
      return true;
   }else{
      alert("User does not want to continue!");
      return false;
   }
//-->
</script>

Answer 2

In your code header("Location: login.php"); is there before your js code so it never execute js code it redirects to login page remove it and try.

Answer 3

Use this code

echo '<script>';
echo 'alert("Password Invalid!");';
echo 'location.href="login.php"';
echo '</script>';

instead of

header("Location: login.php");
echo '<script type="text/javascript">';
echo 'alert("Password Invalid!");';
echo '</script>';

Thanks.

Answer 4

Your code that comes after the header doesn't run, maybe try setting a session variable and check for that variable in login.php. You can then call the alert from there, or just show a simple message on the page.

Answer 5

there is a missing semicolon right behind the alert:

if($conn) {
    $result=sqlsrv_query($conn, "SELECT * FROM Operator
    WHERE Username='{$_POST['login']}'");
    $pass=sqlsrv_fetch_array($result);
    if($pass["Password"] === $_POST['password']) {
        session_start();
        $_SESSION['loggedin']=true;
        header("Location: home.php");
        exit;
    }
    else {
        header("Location: login.php");
        echo '<script type="text/javascript">';
        echo 'alert("Password Invalid!");';
        echo '</script>';
    }
}
sqlsrv_close($conn);

didnt you check the javscript console ?

EDIT: Sorry, my fault, the semicolon isnt necessary of course.

I testet your php code on my server and it works fine anyway !