I presume you're referring to create(). I haven't really focussed on efficiency here; I'm just trying to make it less horrible to work with than the flat DOM methods. The format I'm using here is actually not my own: it's a simple (possibly incomplete?) implementation of JsonML. Ideally, for efficiency and readability, it's better to include the templates in HTML and then make copies of them with cloneNode() as necessary. However, sometimes we really do need to create chunks of markup in code, and this aims to allow the simplicity of innerHTML without sacrificing the standards compliance, readability, and ease of formatting and transformation.