isKanji = function (ch) {
    ch = ch[0];
    return (ch >= "\u4e00" && ch <= "\u9fcf")
        || (ch >= "\uf900" && ch <= "\ufaff")
        || (ch >= "\u3400" && ch <= "\u4dbf");
}
Check if given char is a kanji

@param {string} ch Given char
@return {boolean} if given char is a kanji