function WriteCookie(key, value, days) {
   var str = key + "=" + escape(value) + ";path=/;";
   if (days != 0) {
      var dt = new Date();
      dt.setDate(dt.getDate() + days);
      str += "expires=" + dt.toGMTString() + ";";
   }
   document.cookie = str;
}
function ReadCookie(key) {
   var sCookie = document.cookie;
   var aData = sCookie.split(";");
   var oExp = new RegExp(" ", "g");
   key = key.replace(oExp, "");

   var i = 0;
   while (aData[i]) {
      var aWord = aData[i].split("=");
      aWord[0] = aWord[0].replace(oExp, "");
      if (key == aWord[0]) return unescape(aWord[1]);
      if (++i >= aData.length) break;
   }
   return "";
}
function DeleteCookie(key) {
   var dt = new Date();
   var str = key + "=;path=/;expires=" + dt.toGMTString() + ";";
   document.cookie = str;
}

//ユーザー設定項目
var defSize = 88; //規定サイズ
var Unit = '%'       //単位
var chWidth = 5;  //増減幅
var days = 30;     //クッキー保存日数
//設定項目終わり

var x = defSize;
function SetFontSize(v) {
   if (v > 10 && v < 300) {
      document.body.style.fontSize = v + Unit;
      if (defSize == v){
         DeleteCookie('FontSize');
      }
      else {
         WriteCookie('FontSize', v, days);
      }
      x = v;
   }
}
function FontSizeChange(cv) {
   if (cv == 0){
      SetFontSize(defSize);
   }
   else {
      y = parseInt(x) + cv;
      SetFontSize(y);
   }
}
function ReadFontSize() {  
   fs = ReadCookie('FontSize')
   if (fs != ''){
      SetFontSize(fs);
   }
}