问添加用户名和密码错误消息

EN

if( mysql_num_rows( $login) == 1) 
{
    // Successful login
    $_SESSION['username'] = $_POST['username'];
    ...
}
else
{
    // Invalid login
    echo "Your username or password are incorrect!";
}

if(mysql_num_rows($login) == 1)
{
$SESSION['username'=$_POST['username'];

//Successfull login  redirect to home page
}
else
{
// incorrect username or password
$incorrectLogin_flag =1;
}

<?php

echo "Username : <input type='text' name='username' />";

echo "Username : <input type='password' name='password' />";

echo " <input type='submit' value='Login' />";

echo " <input type='submit' value='Cancel' />";

if($incorrectLogin_flag ==1)
{
 echo" <label style='color:red;'> Username or Password incorrect.</label>";
}

    if(Something goes wrong){

    //display the errors


    }elseif(all goes right){
    //login
    //redirect


    }