function getBoxID(id) {
    if (document.getElementById) return document.getElementById(id);
    if (document.all) return document.all(id);
    return null;
}
function switchBox(n) {
    for ( var i=0; i<4; i++ ) {
		if ( getBoxID( 'topics-box' + i ) ) {
			getBoxID( 'topics-box' + i ).style.display = "none";
		}
	}
    getBoxID( 'topics-box' + n ).style.display = "block";
}