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) {
		navigation_01_over = newImage("images/navigation_01_over.gif");
		navigation_02_over = newImage("images/navigation_02_over.gif");
		navigation_03_over = newImage("images/navigation_03_over.gif");
		navigation_04_over = newImage("images/navigation_04_over.gif");
		preloadFlag = true;
	}
}
function pop_window(theUrl) {
popup=window.open(theUrl, 'popup','width=404,height=400,scrollbars=yes,location=no,resizable=no,status=no,toolbars=no,top=0,left=0');
	popup.focus()
}

function quiz_window() {
quiz=window.open('quiz.html','quiz','width=400,height=300,scrollbars=no,location=no,resizable=no,status=no,toolbars=no,top=0,left=0');
	popup.focus()
}


function toggle( targetId ){
  if (document.getElementById){
  		target = document.getElementById( targetId );
  			if (target.style.display == "none"){
  				target.style.display = "";
  				eval(targetId +"plus").src="images/minus.gif";
  			} else {
  				target.style.display = "none";
  				eval(targetId +"plus").src="images/plus.gif";
  			}
  	}
}