// JavaScript Document - Image Rollover & Preloader

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 imageLoader() {
	if (document.images) {
		pre_index_app = newImage('../assets/images/index_appBut_ov.gif');
		
		pre_nav_ourMissionAndImpact = newImage('../assets/images/nav_ourMissionAndImpactBut_ov.gif');
		pre_nav_theCorpsExperience = newImage('../assets/images/nav_theCorpsExperienceBut_ov.gif');
		pre_nav_afterTheCorps = newImage('../assets/images/nav_afterTheCorpsBut_ov.gif');
		pre_nav_admissions = newImage('../assets/images/nav_admissionsBut_ov.gif');
		pre_nav_aboutUs = newImage('../assets/images/nav_aboutUsBut_ov.gif');
		pre_nav_applyNow = newImage('../assets/images/nav_applyNowBut_ov.gif');
		
		pre_subnav_ourMissionAndImpact = newImage('../assets/images/title_subnav_ourMissionAndImpact_ov.gif');
		pre_subnav_theCorpsExperience = newImage('../assets/images/title_subnav_theCorpsExperience_ov.gif');
		pre_subnav_afterTheCorps = newImage('../assets/images/title_subnav_afterTheCorps_ov.gif');
		pre_subnav_admissions = newImage('../assets/images/title_subnav_admissions_ov.gif');
		pre_subnav_aboutUs = newImage('../assets/images/title_subnav_aboutUs_ov.gif');
		pre_subnav_resource_corpsAlumni = newImage('../assets/images/title_subnav_resourcesCorps_ov.gif');
		pre_subnav_resource_donors = newImage('../assets/images/title_subnav_resourcesDonors_ov.gif');
		pre_subnav_resource_gradSchools = newImage('../assets/images/title_subnav_resourcesGradSchools_ov.gif');
		pre_subnav_resource_friendsFamily = newImage('../assets/images/title_subnav_resourcesFriends_ov.gif');
		pre_subnav_resource_media = newImage('../assets/images/title_subnav_resourcesMedia_ov.gif');
		pre_subnav_resource_staff = newImage('../assets/images/title_subnav_resourcesStaff_ov.gif');
		pre_subnav_resource_researchers = newImage('../assets/images/title_subnav_resourcesResearchers_ov.gif');
		
		pre_left_arrowOpen = newImage('../assets/images/subNav_ico_open.gif');
		pre_left_newsletter = newImage('../assets/images/left_newsletterBut_ov.gif');
		
		pre_left_arrowOpen = newImage('../assets/images/subNav_ico_open.gif');
		pre_left_newsletter = newImage('../assets/images/left_newsletterBut_ov.gif');

		pre_callout_perspectives = newImage('../assets/images/callout_perspectivesBut_ov.gif');
		
		preloadFlag = true;
	};
};
//Subnav menu
var OpenContainer = null;
var OpenMenus = null;
var HideMenuTimer = null;

function menuStartTimeout(hideTimeout) {
	HideMenuTimer = setTimeout("menuHideMenus()", hideTimeout);	
}

function menuHideMenus() {
	menuResetTimeout();
	if(OpenContainer) {
		var c = document.getElementById(OpenContainer);
		c.style.visibility = "inherit";
		OpenContainer = null;
	}
	if( OpenMenus ) {
		for(var i in OpenMenus) {
			var m = document.getElementById(OpenMenus[i]);
			m.style.visibility = "hidden";			
		}
		OpenMenus = null;
	}
}

function menuHideSubmenus(menuName) {
	if( OpenMenus ) {
		var h = false;
		var c = 0;
		for(var i in OpenMenus) {
			if( h ) {
				var m = document.getElementById(OpenMenus[i]);
				m.style.visibility = "hidden";
			} else if( OpenMenus[i] == menuName ) {
				h = true;
			} else {
				c++;
			}
		}
		OpenMenus.length = c+1;
	}
}

function menuOverMenuItem(menuName, subMenuSuffix) {
	menuResetTimeout();
	menuHideSubmenus(menuName);
	if( subMenuSuffix ) {
		var subMenuName = "" + menuName + "_" + subMenuSuffix;
		menuShowSubMenu(subMenuName);
	}
}

function menuShowSubMenu(subMenuName) {
	menuResetTimeout();
	var e = document.getElementById(subMenuName);
	e.style.visibility = "inherit";
	if( !OpenMenus ) {
		OpenMenus = new Array;
	}
	OpenMenus[OpenMenus.length] = "" + subMenuName;
}

function menuResetTimeout() {
	if (HideMenuTimer) clearTimeout(HideMenuTimer);
	HideMenuTimer = null;
}

function menuShowMenu(containName, menuName, xOffset, yOffset, triggerName) {
	menuHideMenus();
	menuResetTimeout();
	menuShowMenuContainer(containName, xOffset, yOffset, triggerName);
	menuShowSubMenu(menuName);
}

function menuShowMenuContainer(containName, x, y, triggerName) {	
	var c = document.getElementById(containName);
	var s = c.style;
	s.visibility = "inherit";
	
	OpenContainer = "" + containName;
}