* Non-Unicode or missing PCRE unicode support: "/[^\S\xa0]/" * Unicode and PCRE unicode support: "/[^\S\P{Z}\xa0]/u" * Unicode and PCRE unicode support in Chinese mode: "/[^\S\P{Z}\P{Lo}\xa0]/u" * if PCRE unicode support is turned ON ("\P" is the negate class of "\p"): * "\p{Z}" or "\p{Separator}": any kind of Unicode whitespace or invisible separator. * "\p{Lo}" or "\p{Other_Letter}": a Unicode letter or ideograph that does not have lowercase and uppercase variants. * "\p{Lo}" is needed for Chinese characters because are packed next to each other without spaces in between. *