enable or disable selection on a node
node = d.byId(node); if(d.isMozilla){ node.style.MozUserSelect = selectable ? "" : "none"; }else if(d.isKhtml){ node.style.KhtmlUserSelect = selectable ? "auto" : "none"; }else if(d.isIE){ node.unselectable = selectable ? "" : "on"; d.query("*", node).forEach(function(descendant){ descendant.unselectable = selectable ? "" : "on"; }); } //FIXME: else? Opera?