问题
What is the value of an em in terms of pixels?
10em = ?px ?
回答1:
There's no specific relationship between em and px. It's computed based on the width of the "m" character for each font-face.
回答2:
While as others have said, there is no set ratio - as it varies from font to font - it is possible to calculate this for a particular font face/size combination by using DHTML.
Simply create a div with
style="width: 1em; visibility:hidden"
and append it to the place in the document you are interested about.
You can then find out its width by checking the div's clientWidth property
回答3:
It depends on the font and the platform you're rendering on. There is no universal ratio.
回答4:
It's about 160px, if 1em is 16px and 10em = 1000%. It's just an approximation, which will depend on font, browser and OS.
回答5:
If you are using a standard sized text font of 11 or 12px then a general rule of thumb is 1em is going to be about that big in pixels, so 11 or 12 pixels.
回答6:
By default 1em is 16px (font-size:100%;), so 16px x 10em = 160px
You can change the size of an em by changing the percent of the font-size in the body, for example if you want to change the size of an em to 10px, this would be your CSS:
body {
font-size:62.5%;
}
16px x 62.5% = 10px
来源：https://stackoverflow.com/questions/1462997/what-is-the-relationship-between-ems-and-pixels