Php-question about the PHP regular expression authentication username? Zhang Si

Basically, but this is not the case. if the user name is changed to Michael Jacob, why? Thank you for your patience. & Quot; Supplement 1: reply to the answer: the blank space contains two spaces, one half-width, and one full-width s. you can use this method, you can also use a single half-width space to OK, and add the full-width filter to James. I just learned this, but I really don't understand it. thank you for your answers. I hope you can solve it. Supplement 2: JS verification can pass Zhang Si! & Quot; if ([& lt; & gt; & #39; & quot;]. test (fm. username. value) {alert (& quot; the user name contains invalid characters & quot;); fm regular php

Basically, but this is not the case. if the user name is changed to Michael Jacob, why? Thank you for your patience.

   \ '\ "\]/'; If (preg_match ($ _ char_pattern, $ _ string) {echo 'user name cannot contain sensitive characters! ';} Else {echo' no sensitive character ';}?>

Supplement 1:

Reply to the answer:
The blank space contains two spaces, one half-width and one full-width space.

\ S can use this function. It can also be OK to use a single half-width space. if you add a full-width filter, James cannot pass through.

I just learned this, but I really don't understand it;

Thank you for your answers. I hope you can solve this problem.

Supplement 2:

JS verification can be passed through James!

If (/[<> \ '\ "\]/. test (fm. username. value) {alert ("the user name contains invalid characters"); fm. username. focus (); return false ;}