This jQuery plugin seems to do exactly this:
https://github.com/johnantoni/jquery.onfontresize
The idea of this plugin is to have an iframe sized in em
and a script in the iframe that is triggered on onresize
. So if the user changes the size of the font in the window the iframe is resized and gets an resize event. This event can then be passed to the parent.
The problem is that the plugin was not updated for 3 years but i don't think it would be a big deal to bring it up to date.
In addition you need to check for the correct font size on document ready
.
EDIT I check it with current jQuery version and IE. The plugin triggers the event if the font size is changeable via View > Text Size
(when the pages font size is set with em
or %
) it the pages font size is set with px
then the size of the font is not changing hence no event is triggered.