/* Browser detection.  Makes sure that browser used is compatible with Javascript code */
var browserName = navigator.appName;
var browserVer = parseInt(navigator.appVersion);
var browserOK = false;

if ((browserName=="Netscape" && browserVer>=3) || (browserName=="Microsoft Internet Explorer" && browserVer>=4))
  browserOK = true; 

  
/* Funtion to preload images */
var pics = new Array();
var preloadFlag = false;

var s = "img";


function preloadImage(imgNumStr, mouseOutImg, mouseOverImg)
{  
	// preload images and place them in an array
	if (browserOK)
	{
		var aNumber = parseInt(imgNumStr);


		if (aNumber != Number.NaN)
		{		
			var index = aNumber-1;

			if (index == pics.length)
			{
				pics[index] = new Array(2);

				pics[index][0] = new Image();
				pics[index][0].src = mouseOutImg;

				pics[index][1] = new Image();
				pics[index][1].src = mouseOverImg;
			}
		}
	}

	return true;
}



/* Swap image on mouseOver() event */
function on(imgNumStr)
{
	if ((browserOK) && (preloadFlag == true))
	{
		var aNumber = parseInt(imgNumStr);


		if (aNumber != Number.NaN)
		{		
			var index = aNumber-1;

			if ((index >= 0) && (index < pics.length))
			{
				document.images[s.concat(imgNumStr)].src = pics[index][1].src;
			}
 	   	}
  	}

	return true;
}


/* Restore image on mouseOut() event */
function off(imgNumStr)
{
	if ((browserOK) && (preloadFlag == true))
	{
		var aNumber = parseInt(imgNumStr);


		if (aNumber != Number.NaN)
		{		
			var index = aNumber-1;

			if ((index >= 0) && (index < pics.length))
			{
				document.images[s.concat(imgNumStr)].src = pics[index][0].src;
			}
		}
  	}

	return true;
}
  

/* Used on drop down menus.  Jumps to selected URL. */
function jumpURL(form)
{  
	if (browserOK)
		if (form.URL.selectedIndex != 0)
			location = form.URL.options[form.URL.selectedIndex].value;

	return true;
};