[TYPO3] developing extension for font-size changes

[Felix Natter]

hi,

I need to have buttons on my site for increasing/decreasing font-size.
There is an extension "dynamicfontsize" for this purpose, but it
is javascript-based and does not support inc/dec buttons
(only supports buttons small/normal/large).

I'd like to develop a solution that is server-based (current font-size
saved in PHP session variable) and that includes a stylesheet file for
the specified font-size.

I thought I'd write a frontend extension that includes the correct
stylesheet based on a session variable and the output of which is
copied into the page header:
page.headerData.11 < tx_MYEXT_pi1

Now I'd set "larger fontsize button"'s href to
index.php?id=PID&fontsize=larger and the extension above would
see this in $_GET and set/adapt the session variable.

This is my first extension. Is this a good approach or can
this be done more easily?

thanks,

-- 
Felix Natter