whats wrong ??? (function)

i have a function for register users

now i what to do, if the username existing
the function give to me a message

i have the register function

function register($username,$password,$firstname,$lastname)
                  {
                      // just  check //
                      $check = mysql_query("SELECT * FROM `test` WHERE username='".mysql_escape_string($username)."' LIMIT 1;");
                      if(mysql_num_rows($check) != 0)
                        {
                         return false;
                        }
                      if (!empty($_POST['username']) && !empty($_POST['password']) && !empty($_POST['firstname']) && !empty($_POST['lastname']))
                       {
                            //smart encoding //
                            $chars = "!a@b$g%^&*()_+=-'\";][\\/:87{}~`";
                             for($i=0;$i<10;$i++)
                                 {
                                   $smart .= $chars[rand() % strlen($chars)-.07];
                                 }

                             // do the pass//
                            $password = MD5($smart.$password.$smart);

                            if(mysql_query("INSERT INTO `test` (`id`,`username`,`password`,`smart`,`firstname`,`lastname`,`time`)
                                            VALUES (NULL, '".mysql_escape_string($username)."', '".$password."', '".$smart."', '".$firstname."', '".$lastname."',UNIX_TIMESTAMP())"))
                              {
                               return true;
                              }
                            return false;
                        }
                      else
                        echo 'plz full all the fild!';
                  }

Code (markup):

and the register page:

<?php

if (isset($_POST['check_if_press']) && $_POST['check_if_press'] == "Send")
          {
              if ( $_POST['password'] == $_POST['confrim'] )
                {
                  if(register ($_POST['username'],$_POST['password'],$_POST['firstname'],$_POST['lastname']) == 'false')
                  echo 'username existing ';
                  register ($_POST['username'],$_POST['password'],$_POST['firstname'],$_POST['lastname']);
                  if(mysql_insert_id())
                   {
                   echo "you are signed in, thx you for registering <br /> ".$_POST['username'];
                   }
                }
              else echo ' your password and confrim not same';
            }



 ?

Code (markup):

plz help me to do that :/

 

This is the function that check whether the username is previously available or not..if the username exists then it will return 1 else it will return 0

function checkUser($memberName)
{
$selectQuery = "SELECT COUNT(*) AS cnt FROM test WHERE userName='$memberName'";
$resultQuery = mysql_query($selectQuery);
$rowQuery = @mysql_fetch_array($resultQuery);
return $rowQuery['cnt']
}

PHP:

Now After you submit the forms..

if(isset($_POST['registerUser']))
{
$userName = $_REQUEST['userName'];
$password = $_REQUEST['password'];
$firstName= $_REQUEST['firstName'];
$lastName= $_REQUEST['lastName'];
$time= date("Y-m-d");
////////////Checking for existing user///////////
$userAvailableStatus = checkUser($userName);
if($userAvailableStatus == 1)
{
echo("<script>alert('User name already taken')</script>");////////////Gives alert message when name is already taken
echo("<script>location.href=''</script>")//////////Redirect according to your wish

}
else
{
$insertQuery = "INSERT INTO test SET username = '$userName',firstName = '$firstName',lastName='$lastName',time='$time'";
mysql_query($insertQuery);
echo("<script>location.href=''</script>")//////////Redirect according to your wish
}
}

PHP:

Cheers
Stylesofts Developing Team