function preload () {
	var pageTitle=document.title;
	xImage= new Array (17);
	for (i=0; i< xImage.length; i++) {
		xImage[i] = new Image ();
	}
	if (pageTitle=="Introduction"){
		document.NavIntro.src="images/NavIntro_Page.gif"
	}
	else if (pageTitle=="Speaker"){
		document.NavSpeaker.src="images/NavSpeaker_Page.gif"
	}
	else if (pageTitle=="Agenda"){
		document.NavAgenda.src="images/NavAgenda_Page.gif"
	}
	else if (pageTitle=="Registration"){
		document.NavReg.src="images/NavReg_Page.gif"
	}
	else if (pageTitle=="Camp"){
		document.NavCamp.src="images/NavCamp_Page.gif"
	}
	else if (pageTitle=="Direction"){
		document.NavDir.src="images/NavDir_Page.gif"
	}
	else if (pageTitle=="Download"){
		document.NavDownload.src="images/NavDownload_Page.gif"
	}
	else if (pageTitle=="History"){
		document.NavHistory.src="images/NavHistory_Page.gif"
	}
	else if (pageTitle=="Login"){
		document.NavLogin.src="../images/NavLogin_Page.gif"
	}
	else if (pageTitle=="List"){
		document.NavList.src="../images/NavList_Page.gif"
	}
	else if (pageTitle=="Statistics"){
		document.NavStatistics.src="../images/NavStatistics_Page.gif"
	}
	else if (pageTitle=="Coworker"){
		document.NavCoworker.src="../images/NavCoworker_Page.gif"
	}
	else if (pageTitle=="Authorize"){
		document.NavAuthorize.src="../images/NavAuthorize_Page.gif"
	}
	else if (pageTitle=="Room"){
		document.NavRoom.src="../images/NavRoom_Page.gif"
	}
	else if (pageTitle=="Other"){
		document.NavOther.src="../images/NavOther_Page.gif"
	}
	else if (pageTitle=="Cashier"){
		document.NavCashier.src="../images/NavCashier_Page.gif"
	}
	else if (pageTitle=="Group"){
		document.NavGroup.src="../images/NavGroup_Page.gif"
	}
	
	//Main Menu Images
	xImage[0].src="images/NavIntro_Over.gif";
	xImage[1].src="images/NavSpeaker_Over.gif";
	xImage[2].src="images/NavAgenda_Over.gif";
	xImage[3].src="images/NavCamp_Over.gif";
	xImage[4].src="images/NavDir_Over.gif";
	xImage[5].src="images/NavReg_Over.gif";
	xImage[6].src="../images/NavLogin_Over.gif";
	xImage[7].src="../images/NavList_Over.gif";
	xImage[8].src="../images/NavStatistics_Over.gif";
	xImage[9].src="../images/NavCoworker_Over.gif";
	xImage[10].src="../images/NavRoom_Over.gif";
	xImage[11].src="../images/NavAuthorize_Over.gif";
	xImage[12].src="../images/NavOther_Over.gif";
	xImage[13].src="../images/NavCashier_Over.gif";
	xImage[14].src="../images/NavGroup_Over.gif";
	xImage[15].src="../images/NavDownload_Over.gif";
	xImage[16].src="../images/NavHistory_Over.gif";
	
}

// swap image when mouse over the button
function SwapImage(img_name,img_src) { 
	eval("document." + img_name + ".src ='" + img_src + ".gif'");
}

// swap image when mouse out the button
function SwapImageBack(img_name,img_src) { 
	var pageTitle=document.title;
	if (pageTitle=="Introduction" && img_src=="images/NavIntro"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Speaker" && img_src=="images/NavSpeaker"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Agenda" && img_src=="images/NavAgenda"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Registration" && img_src=="images/NavReg"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Camp" && img_src=="images/NavCamp"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Direction" && img_src=="images/NavDir"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Download" && img_src=="images/NavDownload"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="History" && img_src=="images/NavHistory"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Login" && img_src=="../images/NavLogin"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="List" && img_src=="../images/NavList"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Statistics" && img_src=="../images/NavStatistics"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Cashier" && img_src=="../images/NavCashier"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Coworker" && img_src=="../images/NavCoworker"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Authorize" && img_src=="../images/NavAuthorize"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Room" && img_src=="../images/NavRoom"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Other" && img_src=="../images/NavOther"){
		img_src=img_src + "_Page"
	}
	else if (pageTitle=="Group" && img_src=="../images/NavGroup"){
		img_src=img_src + "_Page"
	}
	//alert ("document." + img_name + ".src ='" + img_src + ".gif'");
	eval("document." + img_name + ".src ='" + img_src + ".gif'");
}