var type = "unknown";	//Variable used to hold the browser name
var current = "now";    //Variable to hold name of currently dispaying layer
BrowserSniffer();

//detects the capabilities of the browser
function BrowserSniffer() {
	if (document.all) type="all";					//eg Internet Explorer e.g. IE4 upwards
	else if (document.layers) type="layers";		//eg Netscape Communicator 4
	else if (document.getElementById) type="ById";	//eg Opera and Mozila e.g. Netscape 6 upwards
	else type = "unknown";		//I hope it will not get here
}
//Hide one layer and show the next
//id is the name of the layer to show
//action is either hidden or visible
//Seems to work with all versions NN4 plus other browsers
function Swap(id){
	if (type=="all") eval("document.all." + current + ".style.visibility='hidden'");
	if (type=="layers") eval("document." + current + ".visibility='hidden'");
	if (type=="ById") eval("document.getElementById('" + current + "').style.visibility='hidden'");
	if (type=="all") eval("document.all." + id + ".style.visibility='visible'");
	if (type=="layers") eval("document." + id + ".visibility='visible'");
	if (type=="ById") eval("document.getElementById('" + id + "').style.visibility='visible'");
	current = id;
}