function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}
function changeImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}
var preloadFlag = false;
function preloadImages() {
	if (document.images) {
	  var imagesFolder = "http://media.flashcardmachine.com/images/";
		links_Login_over = newImage(imagesFolder+"links_Login-over.gif");
		links_Logout_over = newImage(imagesFolder+"links_Logout-over.gif");
		links_myAccount_over = newImage(imagesFolder+"links_myAccount-over.gif");
		links_Register_over = newImage(imagesFolder+"links_Register-over.gif");
		links_myFlashCards_over = newImage(imagesFolder+"links_myFlashCards-over.gif");
		links_FlashCardDB_over = newImage(imagesFolder+"links_FlashCardDB-over.gif");
		links_TellAFriend_over = newImage(imagesFolder+"links_TellAFriend-over.gif");
		links_Help_over = newImage(imagesFolder+"links_Help-over.gif");
		preloadFlag = true;
	}
}
function writeEmail(host,username,text,extra) {
  document.write("<a href=\"mailto:"+username+"@"+host+"\" "+extra+">");
  if (text) {
    document.write(text);
  } else {
    document.write(username+"\@"+host);
  }
  document.write("</a>");
}
var studyWindow = null;
function launchStudySession(userId,topicId,extraQS)  {
  extraQS = typeof extraQS != "undefined" ? extraQS : "";
  var url = '/Machine/?'+(userId?'USERID='+userId+'&':'')+(extraQS?extraQS+'&':'')+'topic_id='+topicId;
  var winl = (screen.width-600)/2;
  var wint = (screen.height-348)/2;
  if (studyWindow == null || studyWindow.closed) {
    studyWindow = window.open(url,'newWin','width=600,height=348,top='+wint+',left='+winl+',resizable=yes,toolbar=no,location=no,scrollbars=yes');
  } else {
    studyWindow.document.location=url;
  }
  if (studyWindow == null) {
    alert("You have a pop-up blocker preventing the study window from opening. Please add an exception for flashcardmachine.com or disable entirely.");
  } else {
    studyWindow.focus();
  }
}