1234567891011121314151617Regex regex = new Regex(@"[/u00FF-/uFFFF]+");

// The characters, whoes value are smaller than 0xff,

// are not expected to be matched.

for (int i = 0; i < 0xff; i++) {

       string s = new string(new char { (char)i });

       Debug.Assert(!regex.IsMatch(s), string.Format(

                    "The character was not expected to be matched: 0x{0:X}!", i));

}

// However, the characters whoes value

// are greater than 0xfe are expected to be matched.

for (int i = 0xff; i <= 0xffff; i++) {

       string s = new string(new char { (char)i });

       Debug.Assert(regex.IsMatch(s), string.Format(

                    "The character was expected to be matched: 0x{0:X}!", i));

}

1234567891011121314151617var re = /[/u00FF-/uFFFF]+/;

// var re = /[/u00FF-/uFFFF]+/i;

for(var i=0; i<0xff; i++) {

       var s = String.fromCharCode( i );

       if ( re.test(s) ) {

              alert( ''Should not be matched: '' + i + ''!'' );

       }

}

for(var i=0xff; i<=0xffff; i++) {

       var s = String.fromCharCode( i );

       if ( !re.test(s) ) {

              alert( ''Should be matched: '' + i + ''!'' );

       }

}