function change_focus(layer) {
    var item;

    if (document.getElementById) {
        item = document.getElementById(layer);
    } else if (document.all) {
        item = document.all[layer];
    } else if (document.layers) {
        item = document.layers[layer];
    }

    item.focus();
}

function js_getElementById(id)
{
	var element = null;
	
	if ( document.layers ) { // Netscape 4
		element = document.layers[id];
	} else if ( document.all ) { // IE4, IE5
		element = document.all[id];
	} else if( document.getElementById ) { // IE5+
		element = document.getElementById(id);
	}
	
	return element;
}

function toggle_layer(layerId)
{
	var layer = js_getElementById(layerId);
	
	if (layer != null)
	{
		var ls = layer.style;
		ls.display = (ls.display == "" || ls.display == "none" ? "block" : "none");
	}
}

function image_popup(filename) {
    window.open(filename ,'','toolbar=no,status=no,resizable=yes,scrollbars=yes,width=400, height=320');
}