The traditional way to do this with good cross browser support is to use a DOM element. As long as it's not added to -the- DOM (page) the overhead is quite smal

The traditional way to do this with good cross browser support is to use a DOM element. As long as it's not added to -the- DOM (page) the overhead is quite small. When you think about it, creating DOM nodes is pretty much one of the core things for a browser to do, so there's been a lot of optimizations for those things over the years. That doesn't mean that it's pretty. But neither is the DOM API.