To get an em equivalent, do this.

要获得一个em等效值，执行下面的操作。

youdao

Assume the parent font size is 12px. If so, I calculate an em value for 10px as 0.833.

假设父字体大小为12px，如果这样的话，10px的em值为0.833。

youdao

We address this case by supplementing the previous rules with a rule that sets the text color to blue whenever an em occurs anywhere within an h1.

我们这样来改进这一情况：我们对前述的规则补充一个规则，这一规则将出现在H1之内任何位置的EM元素的文本颜色设置为蓝色。

youdao

An electro-magnetic device known as an EM-Bird has also been flown, suspended beneath a helicopter, in long sweeps over the ice.

BBC: Arctic ice melting at 'amazing' speed, scientists find

Dr. Gregory Chavat decided to give us a glimpse of an EM waveform, however, by using a coffee can radar system, a couple of LEDs, and long-exposure photography.

ENGADGET: Man illuminates electromagnetic waves using coffee cans and LEDs, Christmas-colored science ensues

Go ahead and give 'em an idea of the premium you'd pay in comments if these were released in limited quantities.

ENGADGET