function ShowHideLayer(which,show) {
	if (show) {
		if (document.layers) {
			action="show";
		} else {
			action="visible";
		}
	} else {
		action="hidden";
	}
    if (document.getElementById) {
	   	if (document.getElementById(which)) {
			if (document.getElementById(which).style.visibility != action) {
				document.getElementById(which).style.visibility=action;
			}
		}
    } else {
		if (document.layers) {
			if (document.layers[which]) {
				if (document.layers[which].visibility != action) {
					document.layers[which].visibility=action;
				}
			}
		} else {
			if (document.all) {
				if (eval("document.all." + which)) {
					if (eval("document.all." + which + ".style.visibility") != action) {
						eval("document.all." + which + ".style.visibility='" + action + "'");
					}
				}
    		}
		}
	}
}