var cur_layer;
var layer_ref;
var state;
document.write('<style type="text/css">\n');
document.write('#container  {width:505px;}\n');
document.write('#layer_1, #layer_2, #layer_3 {display: none;}\n');
document.write('<\/style>\n');

function swap(layer_ref) {

    function showlayer(layer_ref) {
        var state = 'block';
        if (document.all) {
            eval("document.all." + layer_ref + ".style.display = state");
        }
        if (document.layers) {
            document.layers[layer_ref].display = state;
        }
        if (document.getElementById && !document.all) {
            layer_a = document.getElementById(layer_ref);
            layer_a.style.display = state;
        }
    }
    
    function hidelayer(layer_ref) {
        var state = 'none';
        if (document.all) {
            eval("document.all." + layer_ref + ".style.display = state");
        }
        if (document.layers) {
            document.layers[layer_ref].display = state;
        }
        if (document.getElementById && !document.all) {
            layer_a = document.getElementById(layer_ref);
            layer_a.style.display = state;
        }
    }
    
    function show_hide(layer_ref) {
        if (cur_layer) {
            hidelayer(cur_layer);
        }
        showlayer(layer_ref);
    }

    show_hide(layer_ref);

    cur_layer = layer_ref;
}

cur_layer = 'layer_1';