var userAgent = navigator.userAgent.toLowerCase();
var is_opera  = (userAgent.indexOf('opera') != -1);
var is_saf    = ((userAgent.indexOf('safari') != -1) || (navigator.vendor == "Apple Computer, Inc."));
var is_webtv  = (userAgent.indexOf('webtv') != -1);
var is_ie     = ((userAgent.indexOf('msie') != -1) && (!is_opera) && (!is_saf) && (!is_webtv));
var is_ie4    = ((is_ie) && (userAgent.indexOf("msie 4.") != -1));
var is_moz    = (navigator.product == 'Gecko');
var is_kon    = (userAgent.indexOf('konqueror') != -1);
var is_ns     = ((userAgent.indexOf('compatible') == -1) && (userAgent.indexOf('mozilla') != -1) && (!is_opera) && (!is_webtv) && (!is_saf));
var is_ns4    = ((is_ns) && (parseInt(navigator.appVersion) == 4));

// catch possible bugs with WebTV and other older browsers
var is_regexp = (window.RegExp) ? true : false;

// let's find out what DOM functions we can use
var vbDOMtype = '';
if (document.getElementById) {vbDOMtype = "std";}
else if (document.all) {vbDOMtype = "ie4";}
else if (document.layers) {vbDOMtype = "ns4";}

// make an array to store cached locations of objects called by fetch_object
var vBobjects = new Array();

// function to emulate document.getElementById
function fetch_object(idname, forcefetch)
{
	if (forcefetch || typeof(vBobjects[idname]) == "undefined")
	{
		switch (vbDOMtype)
		{
			case "std":
			{
				vBobjects[idname] = document.getElementById(idname);
			}
			break;
			case "ie4":
			{
				vBobjects[idname] = document.all[idname];
			}
			break;
			case "ns4":
			{
				vBobjects[idname] = document.layers[idname];
			}
			break;
		}
	}
	return vBobjects[idname];
}


// function to toggle the collapse state of an object
function collapse(objid, objidop, imgrep, width, height)
{
	if (!is_regexp)
	{
		return false;
	}
	obj = fetch_object(objid);
	objop = fetch_object(objidop);
	
	if (obj.style.display == "none")
	{
		obj.style.display = "";
		objop.style.display = "none";
		window.document.doc.src=imgrep;
		window.document.doc.width=width;
		window.document.doc.height=height;
	}
	else
	{
		obj.style.display = "none";
		objop.style.display = "";
		window.document.doc.src='images/none.jpg';
		window.document.doc.width='0';
		window.document.doc.height='0';
	}
	return false;
}