I'm writing a simple jQuery that to change the font size of an element by a certain percentage. The problem I'm having is that when I get the size with jQuery's $('#el').css('font-size') it always returns a pixel value, even when set with em's. When I use Javscript's el.style.font-size property, it won't return a value until one has been explicitly set by the same property.

Is there some way I can get the original CSS set font-size value with Javascript? How cross-browser friendly is your method?

Thanks in advance!

Edit: I should note that all the tested browsers (See comment below) allow me to set the the text-size using an 'em' value using the two methods mentioned above, at which point the jQuery .css() returns an equivalent 'px' value and the Javascript .style.fontSize method returns the correct 'em' value. Perhaps the best way to do this would be to initialize the elements on page load, giving them an em value right away.