// For the details, visit ALA:
// http://www.alistapart.com/stories/alternate/

function setActiveTextSize(textsize) {
    document.getElementById('parent').className = textsize;
    createCookie("roybal_textsize", textsize, 365);
    document.getElementById('small').className = '';
    document.getElementById('medium').className = '';
    document.getElementById('large').className = '';
if(textsize=='small') {
    document.getElementById('small').className = 'on';
} else if(textsize=='large') {
    document.getElementById('large').className = 'on';
} else {
    document.getElementById('medium').className = 'on';
}
}

function getActiveTextSize() {
    var textsize = document.getElementById('parent').className;
    if(textsize) {
        return textsize;
    } else {
        return "medium";
    }
}

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+"; domain=usc.edu; 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 = function(e) {
  var cookie = readCookie("roybal_textsize");
  var textsize = cookie ? cookie : "medium";
  setActiveTextSize(textsize);
}

window.onunload = function(e) {
  textsize = getActiveTextSize();
  createCookie("roybal_textsize", textsize, 365);
}