trying to let users use special characters in other languages such as Spanish or French. I originally had this:
"/[^A-Za-z0-9\.\_\- ]/i"
and then changed it to
"/[^\p{L}\p{N}\.\_\-\(\) ]/i"
but still doesn't work. letters such as "ñ" should be allowed. Thanks.
Revision: I found that adding a (*UTF8) at the beginning helps solve the problem. So I'm using the following code:"/(*UTF8)[^\p{L}A-Za-z0-9._- ]/i"
Revision: After looking at the answers I decided to use: "/[^\p{Xwd}. -]/u". Thanks(It works even with the Chinese alphabet.
for latin languages you can use the \p{Latin} character class:
/[^\p{Latin}0-9._ -]/u
But if you want all other letters and digits:
/[^\p{Xwd}. -]/u
The "u" modifier indicates that the string must be read as an unicode string.
You could also look into specifying a unicode range, ie. [\w\u00C0-\u024F.-]+ to include Latin extended letters. But it's hard to try and restrict characters to such a broad subset; what about Chinese, Vietnamese, etc.? I'm with Dagon on this one – best to allow anything.
来源：https://stackoverflow.com/questions/22052517/regular-expression-that-allows-letters-like-%c3%b1-from-any-language