Libra 2 kepub - running Javascript

Hi all,
I want to run the following script in my page, but it crashes because kobo sees the "<" sign as the start of a tag (i think)

It does not seem to replace the text on my page with the correct greeting and time, what am i doing wrong? Adding the //<![CDATA[ tags doesn't seem to change anything.

it does work on an ereader in my browser