//--------------------------------------------//
// Essential Layer version 1.0
//
// Author : Hoi-Hung Tsang (hoi@tsang.cc)
// Lastupd: 4/30/2001
//--------------------------------------------//
// function sequence:
// public:
// 	[1] showLayer
// 	[2] hideLayer
// 	[3] essMakeSearch
// 	[4] getLayerHeader
// 	[5] getLayerFooter
// private:
// 	(6) getStyle



//--------------------------------------------//
// browser Check variables
//--------------------------------------------//
var isNS4 = document.layers ? 1 : 0;
var isIE4 = document.all ? 1 : 0;
var ua = navigator.userAgent.toLowerCase();
var isMAC = (ua.indexOf("mac") != -1);
var isW3C = document.getElementById ? 1 : 0;


//--------------------------------------------//
// show layer
//--------------------------------------------//
// input: [id] -- layer id
// output: none;
//--------------------------------------------//
function showLayer(id) {
	if (id == null) return;
	if (isNS4) {
		eval("document." + id + ".visibility = 'show';");
	} else if (isIE4) {
		document.all[id].style.visibility = "visible";
	} else if (isW3C) {
		eval("document.getElementById('" + id + "').style.visibility = 'visible'");
	}
}


//--------------------------------------------//
// hide layer
//--------------------------------------------//
// input: [id] -- layer id
// output: none;
//--------------------------------------------//
function hideLayer(id) {
	if (id == null) return;
	if (isNS4) {
		eval("document." + id + ".visibility = 'hide';");
	} else if (isIE4) {
		document.all[id].style.visibility = "hidden";
	} else if (isW3C) {
		eval("document.getElementById('" + id + "').style.visibility = 'hidden'");
	}
}


//--------------------------------------------------//
// Create a Layer Header Tag
//--------------------------------------------------//
// input: [id] -- layer id
//				[position] - "absolute" / "relative"
//			  [left] -- layer left most px [0...x]
//				[top] --- layer top most px [0...x]
//				[width] -- layer width [0...x]
//				[height] -- layer height [0...x]
//				[zindex] -- layer stack id
//				[visible] -- true / false
// 				[properties] -- extra attribute, any kind.
// output: none;
//--------------------------------------------------//
function getLayerHeader(id, position, left, top, width, 
												height, zindex, visible, properties)
{
	// setup different platform layer tags
	var dom = "";
	if (isIE4) dom = "DIV";
	else if (isNS4) dom = "LAYER";
	else if (isW3C) dom = "DIV";

	// create header 
	var header = "<" + dom + " ID=\"" + id + "\" ";
	header += getStyle(position, left, top, width, height, zindex, visible);
	if (properties != null)
		header += " " + properties;
	header += ">";

	return header;
}



//--------------------------------------------------//
// Create a Layer Footer Tag
//--------------------------------------------------//
// input: none;
// output: none;
//--------------------------------------------------//
function getLayerFooter()
{
	// setup different platform layer tags
	//var dom = isIE4 ? "DIV" : "LAYER";
	var dom = "";
	if (isIE4) dom = "DIV";
	else if (isNS4) dom = "LAYER";
	else if (isW3C) dom = "DIV";
	return "</" + dom + ">";
}



//--------------------------------------------------//
// Create Layer Style tag
//--------------------------------------------------//
// input: [position] - "absolute" / "relative"
//			  [left] -- layer left most px [0...x]
//				[top] --- layer top most px [0...x]
//				[width] -- layer width [0...x]
//				[height] -- layer height [0...x]
//				[zindex] -- layer stack id
//				[visible] -- true / false
// output: none;
//--------------------------------------------------//
function getStyle(position, left, top, width, height, zindex, visible)
{
	var str = "";
	if (isIE4 || isW3C)
	{
		str = "STYLE=\"";
		if (position != null)
			str += "position:" + position + ";";
		if (left != null)
			str += "left:" + left + ";";
		if (top != null)
			str += "top:" + top + ";"
		if (width != null)
			str += "width:" + width + ";";
		if (height != null)
			str += "height:" + height + ";";
		if (zindex != null)
			str += "z-index=" + zindex + ";";
		if (visible != null)
			str += "visibility:" + (visible == true ? "visible" : "hidden");
		str += "\"";
	}
	else
	{
		if (position != null)
			str += "position=" + position + " ";
		if (left != null)
			str += "left=" + left + " ";
		if (top != null)
			str += "top=" + top + " ";
		if (width != null)
			str += "width=" + width + " ";
		if (height != null)
			str += "height=" + height + " ";
		if (zindex != null)
			str += "z-index=" + zindex + " ";
		if (visible != null)
			str += "visibility=" + (visible == true ? "show" : "hide");
	}
	return str;		
}