var prefsLoaded = false;
var defaultFontSize = 13;
var currentFontSize = defaultFontSize;

function revertStyles(){
        currentFontSize = defaultFontSize;
        changeFontSize(0);
}

function changeFontSize(sizeDifference){
        currentFontSize = parseInt(currentFontSize) + parseInt(sizeDifference);

        if(currentFontSize > 14){
                currentFontSize = 14;
        }else if(currentFontSize < 9){
                currentFontSize = 9;
        }

        setFontSize(currentFontSize);
};

function setFontSize(fontSize){
        document.body.style.fontSize = fontSize + 'px';
};



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 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;
};

window.onload = setUserOptions;

function setUserOptions(){
        if(!prefsLoaded){
                userFontSize = readCookie("fontSize");
                currentFontSize = userFontSize ? userFontSize : defaultFontSize;
                setFontSize(currentFontSize);


                prefsLoaded = true;
        }

}

window.onunload = saveUserOptions;

function saveUserOptions()
{
        createCookie("fontSize", currentFontSize, 30);
}