How can I erase all inline styles with javascript and leave only the styles specified in the css style sheet?

$('div').attr('style', '');

or

$('div').removeAttr('style'); (From Andres’s Answer)

To make this a little smaller, try this:

$('div[style]').removeAttr('style');

This should speed it up a little because it checks that the divs have the style attribute.

Either way, this might take a little while to process if you have a large amount of divs, so you might want to consider other methods than javascript.