var preloadFlag = false;
var mainMenuSrcOn = new Array(11);
var mainMenuSrcOff = new Array(11);
var mainMenuSrcOffNames = new Array(11);
var mainMenusObj = new Array(11);
var subMenusSrc = new Array(10);
var subMenusObj = new Array(10);

mainMenuSrcOn[0] = "images/bl1-on.gif";
mainMenuSrcOn[1] = "images/bl2-on.gif";
mainMenuSrcOn[2] = "images/bl3-on.gif";
mainMenuSrcOn[3] = "images/bl4-on.gif";
mainMenuSrcOn[4] = "images/bl5-on.gif";
mainMenuSrcOn[5] = "images/bl6-on.gif";
mainMenuSrcOn[6] = "images/bl7-on.gif";
mainMenuSrcOn[7] = "images/bl8-on.gif";
mainMenuSrcOn[8] = "images/bl9-on.gif";
mainMenuSrcOn[9] = "images/bl10-on.gif";
mainMenuSrcOn[10] = "images/bl11-on.gif";

mainMenuSrcOff[0] = "images/bl1-off.gif";
mainMenuSrcOff[1] = "images/bl2-off.gif";
mainMenuSrcOff[2] = "images/bl3-off.gif";
mainMenuSrcOff[3] = "images/bl4-off.gif";
mainMenuSrcOff[4] = "images/bl5-off.gif";
mainMenuSrcOff[5] = "images/bl6-off.gif";
mainMenuSrcOff[6] = "images/bl7-off.gif";
mainMenuSrcOff[7] = "images/bl8-off.gif";
mainMenuSrcOff[8] = "images/bl9-off.gif";
mainMenuSrcOff[9] = "images/bl10-off.gif";
mainMenuSrcOff[10] = "images/bl11-off.gif";

mainMenuSrcOffNames[0] = "bl1_off";
mainMenuSrcOffNames[1] = "bl2_off";
mainMenuSrcOffNames[2] = "bl3_off";
mainMenuSrcOffNames[3] = "bl4_off";
mainMenuSrcOffNames[4] = "bl5_off";
mainMenuSrcOffNames[5] = "bl6_off";
mainMenuSrcOffNames[6] = "bl7_off";
mainMenuSrcOffNames[7] = "bl8_off";
mainMenuSrcOffNames[8] = "bl9_off";
mainMenuSrcOffNames[9] = "bl10_off";
mainMenuSrcOffNames[10] = "bl11_off";

subMenusSrc[0] = "images/opeing-innernav-00.gif";
subMenusSrc[1] = "images/opeing-innernav-01.gif";
subMenusSrc[2] = "images/opeing-innernav-02.gif";
subMenusSrc[3] = "images/opeing-innernav-03.gif";
subMenusSrc[4] = "images/opeing-innernav-04.gif";
subMenusSrc[5] = "images/opeing-innernav-05.gif";
subMenusSrc[6] = "images/opeing-innernav-06.gif";
subMenusSrc[7] = "images/opeing-innernav-07.gif";
subMenusSrc[8] = "images/opeing-innernav-08.gif";
subMenusSrc[9] = "images/opeing-innernav-09.gif";

function preloadImages()
{
	if (document.images)
	{
		// load main menu images
		for (i = 0; i < mainMenuSrcOn.length;i++)
		{
			   mainMenusObj[i] = new Image();
			   mainMenusObj[i].src = mainMenuSrcOn[i];
		}
		
		//load sub menu images
		for (i = 0; i < subMenusSrc.length;i++)
		{
			   subMenusObj[i] = new Image();
			   subMenusObj[i].src = subMenusSrc[i];
		}
		preloadFlag = true;
	}
}

function changeImages()
{
	if (document.images && preloadFlag && changeImages.arguments[0] != currentMainMenu)
	{
		for (var i=1; i<changeImages.arguments.length-1; i+=2)
		{
			if ((changeImages.arguments[i+1] != null) && (changeImages.arguments[i] != null))
				document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}