function switchlayer(Layer_Name) {
    
    var GECKO = document.getElementById? 1:0 ;
    var NS = document.layers? 1:0 ;
    var IE = document.all? 1:0 ;

    if (GECKO) {

        document.getElementById(Layer_Name).style.display=
        (document.getElementById(Layer_Name).style.display=='block') ? 'none' : 'block';

    } else if (NS) {

        document.layers[Layer_Name].display=(document.layers[Layer_Name].display==
            'block') ? 'none' : 'block';

    }
    else if (IE) {

        document.all[Layer_Name].style.display=(document.all[Layer_Name].style.display==
            'block') ? 'none' : 'block';

    }
}