Convert full-width digits to half-width (ASCII) digits. 入力値を半角に変換して返却する

toHankaku.js

function toHankaku(original) {
  var result = '';
  for (var i = 0; i < original.length; i = i+1) {
    var tmp = original.charCodeAt(i);
    if ((0xff0f < tmp) && (tmp < 0xff1a)) {
      result += String.fromCharCode(tmp - 0xfee0);
    } else {
      result += String.fromCharCode(tmp);
    }
  }
  return result;
}