Regex to validate usernames

[StickeR]

Ok, somewhile ago I used a regular expression which I found on the internet, to validate email addresses, works fine.

This time around I thought I could modify it, to validate usernames on characters (letters, numbers, - and _ only).

So i cooked up this script:

if (eregi('^[a-zA-Z0-9\_\-]$', $name)) { 
echo 'Valid'; 
} else { 
echo 'Invalid'; 
} 

But whatever I enter as a name, it always gives invalid.
I thought I understood this regular expression thign, but appearantly not.
If anyone could clarify where I messed up, I'd appreciate it.

[eelixduppy]

Try this as you pattern:

$pattern = "/^[a-zA-Z0-9_-]+$/";
if (eregi($pattern, $name)) { 

[StickeR]

Thanks, but no luck.

Tried both 'techniques', but it still comes up as Invalid.

The odd part is it ALWAYS comes up as Invalid, no matter what you enter as $name.
Entering: 'ASdF324' as $name give Invalid (though it should be valid)
Entering: '^@&#@#*(@#{}::><' as $name also give invalid (which should be correct( but shows the ELse isnt reversed or anything.)

[coopster]

Get rid of the anchors and negate the character class (then reverse your logic) ...

if (eregi('[^a-zA-Z0-9\_\-]', $name)) { 
 echo 'Invalid'; 
} else { 
 echo 'Valid'; 
}