username

[asmith]

when  a form says the username can contain only for example letters and numbers , how do it check the username ?

for example if i use uername  abc-123  ,  how can i find out i have used "-" in my username ?

my english bad , i don't want to define all the "not-allowed" characters to find out, i want the backward thing, just check the allows characters, otherwise --> error .

 

[rajivgonsalves]

try this

 

<?
$username = "test";

if (preg_match("/^[a-zA-Z0-9\_\.]+$/",$username))
{
    echo "Valid username";
}
else 
{
    echo "Not a valid username";
}
?>

[asmith]

really thanks , could please tell me what        /^[a-zA-Z0-9\_\.]+$/        means ?

 

as i know preg match will ask , what are you looking for , and where are looking for ,

in what part,  i only understood the a-zA-Z0-9.  but  what those  / ,  ^ , \_\ ,  .    +$    means ??

 

[BenInBlack]

I like to do it in Javascript

 

html input field

<input name=testfield value="hello-there" onblur="removeInvalidChars(this);">

 

Javascript code

function removeInvalidChars(inputObj)
{
	var regSpaces = new RegExp(/([-!@#$%])/g);
	if (regSpaces.test(inputObj.value)) {
		alert('Invalid Characters entered');
		var objval = inputObj.value.replace(/([-!@#$%])/g,'');
		inputObj.value = objval;
	}
}

 

this code also removes the offending chars

[rajivgonsalves]

it means aphabets ABC..Z or abc...z or 012..9 or "_" or "." is allowed

[BenInBlack]

here is a handy link for learning Regex and testing it

http://www.quanetic.com/regex.php

[asmith]

here is a handy link for learning Regex and testing it

http://www.quanetic.com/regex.php

 

really useful , thanks .

 

 

if i want to allow space ,  i should inert a \ \ ?  like

 

if (preg_match("/^[a-zA-Z0-9\_\ \.]+$/",$username))

[rajivgonsalves]

yes that would work

[asmith]

thanks a bunch!

[asmith]

oops ,another thing . how can i make the user be case-sensetive like password?

[rajivgonsalves]

what do you mean case sensitive ?

[asmith]

like these 2 usernames won't be equal  :    "abc"  "aBc"

actually i made a login page, but it doesn't care in the username field whether i type it uppercase , or lower case,

but password is case-sensetive.

 

[rajivgonsalves]

post your code maybe I could help

[asmith]

it is too simple

wen somebody fill the form user and password :

script do this :

 

insert into tableuser values ($_POST[username],$_POST[password]);

 

then in login page,

i have

select * from tableuser where username='$_POST[username]' and password='$_POST[password]'";

.

.

.

i have a test user name "john" , with password "qwerty",

i can log in with this user and password , no problem

but when i type the password "QWERTY" , it won't sign in , cos uppercase and lowercase matters to password.

then again if i type the user "JOHN" and password "qwerty" , it works and sign in , cos uppercase and lowercase letters do not matter to user name ,

i want to know how can makes it matter to username ? like password, uppercase nad lowercase matters.

example :

john  qwerty sign in

JOHN  qwerty won't sign in,