check full width katakana

jvit

echo isFullWidthKatakana('アイウエオ');

=> true

Shortcut: ja.fullWidthKatakana

/**
* fullwidth katakana
*
* @return bool
*/
function isFullWidthKatakana($word)
{
  return preg_match('/^([ァ-ン]|ー)+$/', $word);
}