function link_toggle_category(n) {
	var e = document.getElementById('c' + n);
	
	if (document.defaultView) {
		var v = document.defaultView.getComputedStyle(e, "").getPropertyValue('display');
	}
	else if (e.currentStyle) {
		var v = e.currentStyle['display'];
	}
		
	e.style.display = (v == 'block' ? 'none' : 'block');
	
	return false;
}