function getObj(name) {

        if (document.getElementById) { return document.getElementById(name).style; }
        else if (document.all)        { return document.all[name].style; }
        else if (document.layers) {        return document.layers[name]; }
}
function show_spis() {
        x = getObj("spisksiazek");
        if(x.visibility == 'visible') {
	        x.visibility = 'hidden';
        } else {
	        x.visibility = 'visible';
	    }
}