function Is(){
    var agent = navigator.userAgent.toLowerCase();
    this.major = parseInt(navigator.appVersion);
    this.minor = parseFloat(navigator.appVersion);
    this.ns  = ((agent.indexOf('mozilla')!=-1) && ((agent.indexOf('spoofer')==-1) && (agent.indexOf('compatible') == -1) && (agent.indexOf('netscape') != -1)));
    this.moz = ((agent.indexOf('mozilla')!=-1) && ((agent.indexOf('spoofer')==-1) && (agent.indexOf('compatible') == -1) && (agent.indexOf('netscape') == -1)));
    this.ns2 = (this.ns && (this.major == 2));
    this.ns3 = (this.ns && (this.major == 3));
    this.ns4b = (this.ns && (this.minor < 4.04));
    this.ns4 = (this.ns && (this.major >= 4));
    this.ns6 = (this.ns && (this.major >= 5));	
    this.ie   = (agent.indexOf("msie") != -1);
    this.ie3  = (this.ie && (this.major == 2));
    this.ie4  = (this.ie && (this.major >= 4));
    this.moz = (this.moz && (this.major == 5));
    this.op3 = (agent.indexOf("opera") != -1);
    this.win   = (agent.indexOf("win")!=-1);
    this.mac   = (agent.indexOf("mac")!=-1);
    this.unix  = (agent.indexOf("x11")!=-1);	
}
var is = new Is();

function showlayer(layer1,layer2){
	document.getElementById(layer1).style.visibility = 'visible';
	document.getElementById(layer2).style.visibility = 'visible';
}

function hidelayer(layer1,layer2){
	document.getElementById(layer1).style.visibility = 'hidden';
	document.getElementById(layer2).style.visibility = 'hidden';	
}