The reason is that such thing not existed. It had to be written, and it's really standard stuff.
Also, by the way, but I'm unable to download this, and there are no tests for this, as well as it clearly breaks the XHTML/JavaScript convention.
Thus, even if it's easy to write, it's not easy enough to pluginize it, make accessible for other developers, write tests and keep XHTML/JavaScript separation.
Also, by the way, but I'm unable to download this, and there are no tests for this, as well as it clearly breaks the XHTML/JavaScript convention.
Thus, even if it's easy to write, it's not easy enough to pluginize it, make accessible for other developers, write tests and keep XHTML/JavaScript separation.