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

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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 fr开发者_Python百科om parent elements.

am i missing something?

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i think this site may help with your question

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