页面加载时未定义的索引[重复]

Question

This question already has an answer here:

• “Notice: Undefined variable”, “Notice: Undefined index”, and “Notice: Undefined offset” using PHP 28 answers

the message is

Notice: Undefined index: flag in C:\xampp\htdocs\myfiles\mobile tracking\index.php on line 63

my code is

<?php 
   $stat=$_REQUEST['flag'];
   if($stat=="FAILED")
       {
      echo "Username/password doesnot exists";
   }
?>

</div>

Answer 1

You should check if the $_REQUEST['flag'] variable has been set:

<?php 
$stat= ( isset($_REQUEST['flag']) ? $_REQUEST['flag'] : null) ;
if($stat=="FAILED")
{
    echo "Username/password doesnot exists";
}

?>