what is the difference between css font size using em and percentage? [duplicate]

Question

Possible Duplicate:
Font size in CSS - % or em?

well i was trying to understand the different sizing options in css and i got lost between ems and percentage.
they seems to be the same i mean 1em = 150% and 1.5em = 150%.
and they do cascade too from parent elements.
am i missing something?

Answer 1

i think this site may help with your question

http://kyleschaeffer.com/best-practices/css-font-size-em-vs-px-vs-pt-vs/