CSS / EM & EX

[zeidhaddadin]

Hi all, I have a "Web app development" exam 2morrow and I have this question about em and ex relative mesurement:Em is defined in w3schools as: one em is equal to the current font size of the current element.I didn't understand,, I mean what is the current font size of the current element?also the ex.and also can anyone tell me how to compare the em for example with pt..Thanks in advance,zeid

[vchris]

It means the default em size is 1em and I pretty sure it's equal to 12 pt. Try it yourself on a page. Create 1 paragraph in 1em and another in 12pt.never heard of ex.

[jlhaslip]

Isn't an 'em' the width taken by a lower-case letter 'm' at the current Font-size?

[boen_robot]

If we believe W3Schools, then it has to be the current font size.And by "current", they mean either the default font the browser has specified for itself, OR the font we've specified for a parent element.Different browsers have different default fonts, so "em" is always very relative, unless you specify a font with pixels and then use "em"s on the elements' childs.As for "ex". According to the reference it's "the x-height of a font (x-height is usually about half the font-size)". In other words, the height of the letter "X" in the current font. That height again varies, depening on the font family.