<!--
function set_default_kat( default_kat ) {
    if ( default_kat != '' ) {
        document.forms['references'].current_kat.value = default_kat;
        var elem = document.getElementById( default_kat );
        elem.style.display = '';
    }
}


function show_kat( katname ) {
    if ( document.references.current_kat.value != '' ) {
        var old_elem = document.getElementById( document.references.current_kat.value );
        old_elem.style.display = 'none';
        document.references.current_kat.value = '';
    }

    if ( katname != '' ) {
        var elem = document.getElementById( katname );
        if ( elem.style.display == 'none' ) {
       	    elem.style.display = '';
       	    document.references.current_kat.value = katname;
        }
    }
}
//-->