How to validate unicode characters?

I have one registra开发者_运维百科tion form, I don't want people to register login username with unicode characters. How can i put server side validation PHP + client side validation javascript or jquery.

Please kindly help me out. Thank you.

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Well do you mean outside of normal ASCII range?

You could implement one of the many seemsLikeUtf8() function floating around on the net.

Or do a quick regular expression

if ( ! preg_match('/^[a-z0-9-]+$/i', $username)) {
   echo 'error';
}

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A simple regular expression would do:

if (!username.match(/^[a-zA-Z0-9_+]+$)) {
   alert("invalid username");
}

This will check that the username contains only the characters a-z (upper and lower case), the digits 0-9, '_' and '+'. If you want to extend it to allow other characters, you'll just need to look up a bit more about regular expressions.

On the server-side, you'd do exactly the same thing, since PHP also supports regular expressions.