var min=8;
var max=18;
var changes = 0;
function createCookie(name,value,days) {
        if (days) {
               var date = new Date();
               date.setTime(date.getTime()+(days*24*60*60*1000));
               var expires = "; expires="+date.toGMTString();
        }
        else var expires = "";
        document.cookie = name+"="+value+expires+"; path=/";
}
 
function readCookie(name) {
        var nameEQ = name + "=";
        var ca = document.cookie.split(';');
        for(var i=0;i < ca.length;i++) {
               var c = ca[i];
               while (c.charAt(0)==' ') c = c.substring(1,c.length);
               if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
        }
        return null;
}
 
function eraseCookie(name) {
        createCookie(name,"",-1);
}
function cookieExist(name) {
                if (readCookie(name) != null) {
                                return true;
                } else {
                                return false;
                }
}
function increaseFontSize() {
var p = $('content').descendants();
   for(i=0;i<p.length;i++) {
      if(p[i].style.fontSize) {
         var s = parseInt(p[i].style.fontSize.replace("px",""));
      } else {
         var s = 12;
      }
      if(s!=max) {
         s += 1;
      }
      p[i].style.fontSize = s+"px"
   }
   changes += 1;
   createCookie('fontSize', changes);
}
function decreaseFontSize() {
  var p = $('content').descendants();
   for(i=0;i<p.length;i++) {
      if(p[i].style.fontSize) {
         var s = parseInt(p[i].style.fontSize.replace("px",""));
      } else {
         var s = 12;
      }
      if(s!=min) {
         s -= 1;
      }
      p[i].style.fontSize = s+"px"
   }  
   changes -= 1;
   createCookie('fontSize', changes);
}
function increaseFontSizeBy(gap) {
   var p = $('content').descendants();
   for(i=0;i<p.length;i++) {
      if(p[i].style.fontSize) {
         var s = parseInt(p[i].style.fontSize.replace("px",""));
      } else {
         var s = 12;
      }
      if(s < max) {
         s += gap;
      }
      p[i].style.fontSize = s+"px"
   }
}
 
function updateFontSizeOnLoad() {
        if(cookieExist('fontSize')) {
                changes = parseInt(readCookie('fontSize'));
                increaseFontSizeBy(changes);
               return true;
        }
}