做点什么呢？ 网址错误

I have a login screen. When you type a wrong password/username, you'll be redirected to the same page, but I want to show an error, so I redirect to index.php?wrong.

Now I want to check:

If ?wrong  {
echo "wrong pw"; 
} else {
// nothing
}

I'd like to know how to make this. What do I have to write instead of

if ?wrong

I checked some pages about it, for example this one, but its about index.php?something=wrong, but I'd like to have just ?wrong.

Thanks a lot! Art

<?php

if (isset($_GET['wrong'])) {
    // wrong
}

Try with

if(isset($_GET['wrong']))
{
    //Play
}

$_GET is the global default PHP 'array', which contains all the url parameters. So use this:

<?php
if (isset($_GET['wrong'])) {
  // do stuff
}
?>

isset checks if $_GET['wrong'] is valid, in other words, there is wrong as a parameter somewhere in the url, so what you were asking for (?wrong or ?foo&wrong) will both be detected.