php user registration form problem

[meancity]

<?php
include("./include/db_connect.php");
$presql="select username from kuser";
$preresult=mysql_query($presql, $db);

/// check whether the required fields have been filled or not.

if(empty($username)||empty($password) ||empty($password1)||empty($name)||empty($mail))
{
 header("Location: register.html?error=1");
 exit;
} 


elseif($preresult){
     while($row=mysql_fetch_array($preresult))
     {

     if($username==$row['username'])
       {
        header("Location: register.html?error=2");
        exit;
        }

    }

 }//elseif end


elseif($password !=$password1) //check the passwords.
{
    header("Location: register.html?error=3");
    exit;
}



else { 
//regist the user
}

in the register.html file it includes some php like

<?php
include("./menu.php");

switch ($error) {
    case 1:
        print "<FONT SIZE=\"4\" COLOR=\"#FF0066\">Please fill in the fields reqired...</font>";
        break;

case 2:
    print "<FONT SIZE=\"4\" COLOR=\"#FF0066\">The username is in use....</FONT>";
    break;

case 3:
    print "<FONT SIZE=\"4\" COLOR=\"#FF0066\">re-typed password is not matched</font>";
    break;
} 

?>

it checks
whether then username is in use,
whether required info is filled.
and
whether password and re-type password is matched.

but i sitll can't make it work
can anyone exam my code. appreciate in advanced...

i CAN redirect the user to the registration form if their fills are invalid.
such as username in use, password and re-type password mismatch and required fields unfilled.

yet now ...

i try to fill the registration form in a properly.
it just display a blank, can not regist the user.
if i disable all those if, elseif and else, then it is ok to register a user...
strange.....

thank you thank u thank u...

[batman]

Well...first of all, I do not get this part of your code:

if($username==$row['username'])
           {
            header("Location: register.html?error=2");
            exit;
            }

I read this code like this: If the username they gave to the form matches the username of the database correctly, then it will send them to an error?? Does that make sense?? I think what you meant to do is this:

if($username != $row['username'])
           {
            header("Location: register.html?error=2");
            exit;
            }

Also, what are you doing when the information clears?? you just have it commented out in the script above. What normally goes there??

One more thing. Why are you mixing html and php?? Just make it all php. It would be the easiest thing to do.

Anyways, let me know if that works.
-Blake

[meancity]

as title mentioned it is a user registration form
so when user pick up some username that is already registered by other user... then warnning need to return

why do i mix html and php????

ermm php is html embeded server side script if not mistaken.
different peoplo has different coding style. nothing to question...

somemore, people do always embed php and html a lot. that is what i think how php should go...

do i make myself clear?

forgive me for my lousy english..
thanks for help, do read my post and give meaningful suggestion

appreciate in advance

[batman]

Well...I just had a misunderstanding on your code and what you were doing. Now that you mention it with a little more clearity it is as always more clear to the person reading your post.

I took your code as a login page, not a register page, and I'm sorry if I made you mad.

Now for the code. If you are trying the code you posted below, then if you fill out the form correctly you should be getting just a blank page. In your code you have all the checking stuff, but you don't actually have the registering stuff.
This:

else { 
//regist the user
}

Is nothing.

You will have to, put below the comment, a little script that will enter the info provided into a database, then anything else you want from there.

-Blake