I'm very happy with this plugin ( http://davecardwell.co.uk/javascript/jquery/plugins/jquery-em/ ) but I can't work out how to establish what the initial (default) em width was.
I'm using it to get rid of background images, which will only tolerate 1x size increase (about 20%, I think). If I increase the font size and then decrease it, jQEm restores the default stylesheet. This isn't appropriate if the fonts are still extra-large. Any advice? Cherry