function setActiveStyleSheet(title) {
  var i, a, main;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if(a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("rel").indexOf ("alt") != -1) {
      a.disabled = true;
      if(a.getAttribute("title") == title) a.disabled = false;
    }
  }

  if(document.getElementById)
  {
    var imageTagSmall = document.getElementById('fssmall');
    var imageTagNormal = document.getElementById('fsnormal');
    var imageTagLarge = document.getElementById('fslarge');
    var imageTagLargest = document.getElementById('fslargest');

    if(imageTagSmall && imageTagNormal && imageTagLarge && imageTagLargest){
    switch (title) {
	  case 'largest' : 
		imageTagSmall.src = 'images/DOTARS_fs_off_01.gif';
		imageTagNormal.src = 'images/DOTARS_fs_off_02.gif';
		imageTagLarge.src = 'images/DOTARS_fs_off_03.gif';
		imageTagLargest.src = 'images/DOTARS_fs_on_04.gif';
	        break;
	  case 'large' : 
		imageTagSmall.src = 'images/DOTARS_fs_off_01.gif';
		imageTagNormal.src = 'images/DOTARS_fs_off_02.gif';
		imageTagLarge.src = 'images/DOTARS_fs_on_03.gif';
        	imageTagLargest.src = 'images/DOTARS_fs_off_04.gif';
	        break;
	  case 'normal' : 
		imageTagSmall.src = 'images/DOTARS_fs_off_01.gif';
		imageTagNormal.src = 'images/DOTARS_fs_on_02.gif';
		imageTagLarge.src = 'images/DOTARS_fs_off_03.gif';
	        imageTagLargest.src = 'images/DOTARS_fs_off_04.gif';
	        break;
	  case 'small' : 
		imageTagSmall.src = 'images/DOTARS_fs_on_01.gif';
		imageTagNormal.src = 'images/DOTARS_fs_off_02.gif';
		imageTagLarge.src = 'images/DOTARS_fs_off_03.gif';
	        imageTagLargest.src = 'images/DOTARS_fs_off_04.gif';
	        break;
	}
	}
  }
}

function getActiveStyleSheet() {
  var i, a;
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if(a.getAttribute("rel").indexOf("alternate") != -1 && a.getAttribute("title") && !a.disabled) return a.getAttribute("title");
  }
  return null;
}

function getPreferredStyleSheet() {
  return ('normal');
}

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;
}

function onload () {
  var cookie = readCookie("style");
  var title = cookie ? cookie : getPreferredStyleSheet();
  setActiveStyleSheet(title);
  
  // open the print dialog if required
  for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if(a.getAttribute("title").indexOf("print") != -1)  {
      window.print ();
      break;
    }
  }
}

window.onunload = function(e) {
  var title = getActiveStyleSheet();
  createCookie("style", title, 365);
}