function _show(_id){
document.getElementById(_id).style.display='block';
}

function _hide(_id){
document.getElementById(_id).style.display='none';
}

navigation = function() {
	var as = document.getElementById("tabs").getElementsByTagName("a");
	for (var i=0; i<5; i++) {
		as[i].onclick=function() {
			if (this.className.length<6) {
			for (var j=0; j<5; j++) {as[j].className=""}
			this.className="active"; }
		}

	}
}

function layers(id) {
	var layers = new Array(5);
	layers[0]=document.getElementById("f1");
	layers[1]=document.getElementById("f2");
	layers[2]=document.getElementById("f3");
	layers[3]=document.getElementById("f4");
	layers[4]=document.getElementById("f5");
	for (var k=0; k<5; k++) {layers[k].className="block"}
	var object=document.getElementById(id);
	object.className="activeframe";	
}