function hideAll() {
        // Tenemos que obtener la versión del browser utilizada.
        switch(navigator.family) {
        case 'nn4':
			// Vamos a revisar todos los formularios.
	        for(indice=0;;indice++) {
                if(eval("document.layers.dform"+indice)) {
                    // ocultar.
                    eval("document.layers.dform"+indice+".visibility='hidden'");
                } else {
                    break;
                }
            }
            break;
        case 'ie4': 
		case 'gecko':
            // Versión de Netscape 6.
            for(indice=0;;indice++) {
                theForm=document.getElementById("dform"+indice);
                if(theForm) {
                    if(theForm.style.visibility=='visible' ||
                       theForm.style.display != 'none') {
                       theForm.style.display='none';
                       theForm.style.visibility='hidden';
                    }
                } else {
                    break;
                }
            }
        }
    }

    function showLayer(theLayer) {
        hideAll();
        switch(navigator.family) {
        case 'nn4':
			dLayer=eval("document.layers."+theLayer);
			break;
		case 'ie4':
        case 'gecko':
            // Tenemos un Netscape 6.
            dLayer=document.getElementById(theLayer).style;
            break;
        }

        if(navigator.family != 'nn4') {
			dLayer.display='block';
			dLayer.visibility='visible';
        } else {
			dLayer.visibility='show';
		}
    }

    function changeLayer(theLayerToShow,theLayerToHide) {
		hideLayer(theLayerToHide);
        switch(navigator.family) {
        case 'nn4':
			dLayer=eval("document.layers."+theLayerToShow);
			break;
		case 'ie4':
        case 'gecko':
            // Tenemos un Netscape 6.
            dLayer=document.getElementById(theLayerToShow).style;
            break;
        }

        if(navigator.family != 'nn4') {
			dLayer.display='block';
			dLayer.visibility='visible';
        } else {
			dLayer.visibility='show';
		}
    }
    function hideLayer(theLayer) {
// Tenemos que obtener la versión del browser utilizada.
        switch(navigator.family) {
        case 'nn4':
			// Vamos a revisar todos los formularios.
                if(eval("document.layers."+theLayer)) {
                    // ocultar.
                    eval("document.layers."+theLayer+".visibility='hidden'");
                } else {
                    break;
                }
            break;
        case 'ie4': 
		case 'gecko':
            // Versión de Netscape 6.
            
                theForm=document.getElementById(theLayer);
                if(theForm) {
                    if(theForm.style.visibility=='visible' ||
                       theForm.style.display != 'none') {
                       theForm.style.display='none';
                       theForm.style.visibility='hidden';
                    }
                } else {
                    break;
                }
            
        }
    }