If you're looking for a very small (~10K), dependency-free alternative to react, check out http://mithril.js.org/, which is far more powerful and from which it seems this project has taken some inspiration (mount, props, and the general syntax are a few of the similarities I see).
If you like React but want to avoid a build system, you can always do
var form = React.createFactory('form');
form({...}, ...);
var e = React.createElement;
e('form', {...}, ...);Check out my other project as well: https://frzr.js.org - it's quite similar but with a bit easier syntax :)
On the one hand this seems far too clever for it's own good and in the same vein as coffeescript where it's really easy for you to write efficient & compact code which somehow turns into complete garbage when you try to read it two weeks later.
On the other hand it looks super neat, has 0 dependencies and looks like React but without requiring any kind of build system.
I think I might need to try it in a side project.