• Source 
    1. function asc(args){
    2.   if (typeof args == "string") {
    3.     // 全角カタカナ⇒半角カタカナ
    4.  
    5.     //変換テーブル：2つの配列の要素数が一致しない場合空白文字が戻り値になる、かならず揃えること
    6.     //replace_table_base:変換対象(検索)文字(wchar_t)
    7.     //replace_table_to:置換文字(wchar_t)
    8.     //ッ, ヮ, ワ, ヰ, ヱ, ヲ, ン, ヵ, ヶ
    9.     var replace_table_base = [
    10.       0x30c3, 0x30ee, 0x30ef, 0x30f0, 0x30f1, 0x30f1, 0x30f3, 0x30f5, 0x30f6
    11.     ]
    12.     var replace_table_to = [
    13.       0xff6f, 0xff9c, 0xff9c, 0xff72, 0xff74, 0xff66, 0xff9d, 0xff76, 0xff79
    14.     ]
    15.     if(replace_table_base.length != replace_table_to.length) return "";//プログラミングミス防止
    16.     // 変換テーブルによる変換
    17.     for(var i = 0; i < replace_table_to.length; i++){
    18.       args = args.replace(new RegExp(String.fromCharCode(replace_table_base[i]), "g"), String.fromCharCode(replace_table_to[i]));
    19.     }
    20.  
    21.     args = args.replace(/ヴ/g, "ｳﾞ");
    22.  
    23.     args = args.replace(/[ァ-オ]/g, function(s){
    24.       var c1 = s.charCodeAt(0);
    25.       var c2 = c1 / 2;
    26.       if(c1 % 2){
    27.         return String.fromCharCode(c2 + 0xe717);//小さいカナ
    28.       }
    29.       else{
    30.         return String.fromCharCode(c2 + 0xe720);//普通のかな
    31.       }
    32.     });
    33.     args = args.replace(/[カ-ヂ]/g, function(s){
    34.       var c1 = s.charCodeAt(0);
    35.       var c2 = c1 / 2;
    36.       if(c1 % 2){
    37.         return String.fromCharCode(c2 + 0xe721);//無濁点
    38.       }
    39.       else{
    40.         return String.fromCharCode(c2 + 0xe720, 0xff9f);//有濁点
    41.       }
    42.     });
    43.     args = args.replace(/[ツ-ド]/g, function(s){
    44.       var c1 = s.charCodeAt(0);
    45.       var c2 = c1 / 2;
    46.       if(c1 % 2){
    47.         return String.fromCharCode(c2 + 0xe720, 0xff9f);//有濁点
    48.       }
    49.       return String.fromCharCode(c2 + 0xe720);
    50.     });
    51.     args = args.replace(/[ナ-ハ]/g, function(s){
    52.       return String.fromCharCode(s.charCodeAt(0) + 0xcebb);
    53.     });
    54.     args = args.replace(/[バ-ポ]/g, function(s){
    55.       var c1 = s.charCodeAt(0);
    56.       var c2 = c1 / 3;
    57.       switch(c1 % 3){
    58.         case 2:
    59.           return String.fromCharCode(c2 + 0xEF45, 0xff9f);//ﾟ
    60.           break;
    61.         case 1:
    62.           return String.fromCharCode(c2 + 0xEF45, 0xff9e);//ﾞ
    63.         default:
    64.           return String.fromCharCode(c2 + 0xEF45);
    65.           break;
    66.       }
    67.     });
    68.     args = args.replace(/[マ-モ]/g, function(s){
    69.       return String.fromCharCode(s.charCodeAt(0) + 0xceb1);
    70.     });
    71.     args = args.replace(/[ャ-ョ]/g, function(s){
    72.       var c1 = s.charCodeAt(0);
    73.       var c2 = c1 / 2;
    74.       if(c1 % 2){
    75.         return String.fromCharCode(c2 + 0xe6fb);//小さいカナ
    76.       }
    77.       else{
    78.         return String.fromCharCode(c2 + 0xe722);//普通のかな
    79.       }
    80.     });
    81.     args = args.replace(/[ヨ-ロ]/g, function(s){
    82.       return String.fromCharCode(s.charCodeAt(0) + 0xceae);
    83.     });
    84.  
    85.     return args;
    86.   } else {
    87.     var s = "";
    88.     for (var i = 0; i < args.length; i++) {
    89.       s += args[i];
    90.     }
    91.     return s;
    92.   }
    93. }