var imgHomeOn = new Image();
var imgHomeOff = new Image();
var imgProductsOn = new Image();
var imgProductsOff = new Image();
var imgServicesOn = new Image();
var imgServicesOff = new Image();
var imgForumOn = new Image();
var imgForumOff = new Image();
var imgMembershipOn = new Image();
var imgMembershipOff = new Image();
var imgNewsletterOn = new Image();
var imgNewsletterOff = new Image();
var imgAboutOn = new Image();
var imgAboutOff = new Image();

imgHomeOn.src = "img/btn_home_on.jpg";
imgHomeOff.src = "img/btn_home.jpg";
imgProductsOn.src = "img/btn_products_on.jpg";
imgProductsOff.src = "img/btn_products.jpg";
imgServicesOn.src = "img/btn_services_on.jpg";
imgServicesOff.src = "img/btn_services.jpg";
imgForumOn.src = "img/btn_forum_on.jpg";
imgForumOff.src = "img/btn_forum.jpg";
imgMembershipOn.src = "img/btn_membership_on.jpg";
imgMembershipOff.src = "img/btn_membership.jpg";
imgNewsletterOn.src = "img/btn_newsletter_on.jpg";
imgNewsletterOff.src = "img/btn_newsletter.jpg";
imgAboutOn.src = "img/btn_about_on.jpg";
imgAboutOff.src = "img/btn_about.jpg";

boolNeedRecalculate = false;

function fToggleDiv(strDiv) {
	var objDiv = document.getElementById(strDiv);
	if(objDiv.style.visibility == "hidden") {
		fShow(strDiv);
	} else {
		fHide(strDiv);
	}
}
	
function fShow(strID) {
	var oDiv = document.getElementById(strID);
	oDiv.style.visibility = "visible";
	oDiv.style.display = "block";
}

function fHide(strID) {
	var oDiv = document.getElementById(strID);
	oDiv.style.visibility = "hidden";
	oDiv.style.display = "none";
}

function fMax(intValue, intMax) {
	if(intValue > intMax) {
		return intMax;
	}
	return intValue;
}

function fSetAlpha(strID, intAlpha) {
	if (intAlpha == 0) {
		document.getElementById(strID).style.visibility = "visible";
	}
	document.getElementById(strID).style.MozOpacity = intAlpha / 100;
	document.getElementById(strID).style.filter = "alpha(Opacity=" + intAlpha + ")";
}

function usingIE() {
	if(navigator.appName == "Microsoft Internet Explorer") { return true; }
	return false;
}

function fViewImage(strImage, intWidth, intHeight) {
	window.open("viewImage.php?txtImage=" + strImage, "ImagePreview", "width="+intWidth+",height="+intHeight);
}



function fAJAXRequest(strTarget, strURL) {
	if(window.XMLHttpRequest) {
		oRequest = new XMLHttpRequest();
		oTarget = strTarget;
		oRequest.onreadystatechange = fAJAXChangeWhenReady;
		oRequest.open("GET", strURL, true);
		oRequest.send(null);
	} else if(window.ActiveXObject) {
		oRequest = new ActiveXObject("Microsoft.XMLHTTP");
		if(oRequest) {
			oTarget = strTarget;
			oRequest.onreadystatechange = fAJAXChangeWhenReady;
			oRequest.open("GET", strURL, true);
			oRequest.send();
		}
	}
}

function fAJAXChangeWhenReady() {
	if(oRequest.readyState == 4) {
		document.getElementById(oTarget).innerHTML = oRequest.responseText;
	}
}

function fAddToCart(strCategory, strID) {
	strURL = "cart_bug.php?txtID=" + strID + "&txtCategory=" + strCategory;
	fAJAXRequest("divCart", strURL);
}

function fAJAXCheckUsernameRequest(strTarget, strURL) {
	if(window.XMLHttpRequest) {
		oRequest = new XMLHttpRequest();
		oTarget = strTarget;
		oRequest.onreadystatechange = fAJAXCheckUsernameChangeWhenReady;
		oRequest.open("GET", strURL, true);
		oRequest.send(null);
	} else if(window.ActiveXObject) {
		oRequest = new ActiveXObject("Microsoft.XMLHTTP");
		if(oRequest) {
			oTarget = strTarget;
			oRequest.onreadystatechange = fAJAXCheckUsernameChangeWhenReady;
			oRequest.open("GET", strURL, true);
			oRequest.send();
		}
	}	
}

function fAJAXCheckUsernameChangeWhenReady() {
	if(oRequest.readyState == 4) {
		if(oRequest.responseText != "") {
			boolCanContinue = false;
			alert(oRequest.responseText);
		} else {
			boolCanContinue = true;
		}
		document.getElementById(oTarget).innerHTML = "<span style='color:#ff0000;'>" + oRequest.responseText + "</span><br />";
	}
}

function fCheckUsername(strUsername) {
	strURL = "check_username.php?txtName=" + strUsername;
	fAJAXCheckUsernameRequest("divUsernameLabel", strURL);
}

function fCheckout() {
	if(boolNeedRecalculate) {
		document.getElementById("hdnNextURL").value = "gather_delivery_information.php";
		document.getElementById("frmRecalculate").submit();
		return false;
	} else {
		return true;
	}
}

function fBillingSame(boolSame) {
	document.getElementById("txtShippingName").disabled = boolSame;
	document.getElementById("txtShippingCompany").disabled = boolSame;
	document.getElementById("txtShippingAddressLine1").disabled = boolSame;
	document.getElementById("txtShippingAddressLine2").disabled = boolSame;
	document.getElementById("txtShippingCity").disabled = boolSame;
	document.getElementById("txtShippingState").disabled = boolSame;
	document.getElementById("txtShippingZipcode").disabled = boolSame;
}