validating username

[sudhakararaog]

i have used the following code to validate the username it is working fine

 

=============================================

if( $username == "" ||  !preg_match("/^[a-z0-9]+(?:_[a-z0-9]+)?$/i", $username) )

{

$error.="User name cannot be blank or has special characters";

}

=============================================

 

it does not accept UNDERSCORE at the beginning or end however while i was testing with different special characters except for # the validation works fine for all other special characters.

 

for example if i enter the user name as = abc#123

 

in this case # sign and what comes after # sign is being ignored. so in this case the username is being read as abc ONLY and not abc#123

 

this is very strange, how can i still validate # sign and tell the user that # sign is not a valid username like i have been doing with any other special characters like = !@$...........

 

please advice.

 

thanks.

 

[Dathremar]

I am using this function for checking a valid username:

 

function Valid_username($username)

{   

    if (ereg('^[a-zA-Z0-9]+$', $username))

          return true;

    else

          return false;  

}

 

and it does take into consideration the # character. Try it out.

[sasa]

Where is $username setup?

[tomtom]

Sasa.

 

function Valid_username($username)
{     
    if (ereg('^[a-zA-Z0-9]+$', $username))
           return true;
    else
           return false;         
}

 

That's the function, $username is a variable. So when you call the function, you replace $username with whatever.

 

So you'd have that above your code. Then say a user submitted a username (e.g $_POST[username]); you could then do...

<?php
    if(Valid_username({$_POST['username']})) {
        // Valid_username has returned true, so the username is valid
        echo "Wahay! The username is valid!";
    }else{
        // Valid_username has returned false, so the username isn't valid
        echo "That username is not valid, sorry!";
    }
?>