HTML
<em>
element
marks text that has stress emphasis. The
<em>
element can be nested, with each level of nesting indicating a greater degree of emphasis.
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| 内容类别 | 流内容 , 措词内容 ，可触及内容。 |
|---|---|
| 准许内容 | 措词内容 . |
| Tag omission | None, both the starting and ending tag are mandatory. |
| Permitted parents | Any element that accepts 措词内容 . |
| Implicit ARIA role | 无对应角色 |
| Permitted ARIA roles | 任何 |
| DOM 接口 |
HTMLElement
Up to Gecko 1.9.2 (Firefox 4) inclusive, Firefox implements the
HTMLSpanElement
interface for this element.
|
此元素只包括 全局属性 .
<em>
element is for words that have a stressed emphasis compared to surrounding text, which is often limited to a word or words of a sentence and affects the meaning of the sentence itself.
Typically this element is displayed in italic type. However, it should not be used simply to apply italic styling; use the CSS
font-style
property for that purpose. Use the
<cite>
element to mark the title of a work (book, play, song, etc.). Use the
<i>
element to mark text that is in an alternate tone or mood, which covers many common situations for italics such as scientific names or words in other languages. Use the
<strong>
element to mark text that has greater importance than surrounding text.
New developers are often confused at seeing multiple elements that produce similar results.
<em>
and
<i>
are a common example, since they both italicize text. What's the difference? Which should you use?
By default, the visual result is the same. However, the semantic meaning is different. The
<em>
element represents stress emphasis of its contents, while the
<i>
element represents text that is set off from the normal prose, such a foreign word, fictional character thoughts, or when the text refers to the definition of a word instead of representing its semantic meaning. (The title of a work, such as the name of a book or movie, should use
<cite>
)。
This means the right one to use depends on the situation. Neither is for purely decorational purposes, that's what CSS styling is for.
An example for
<em>
could be: "Just
do
it already!", or: "We
had
to do something about it". A person or software reading the text would pronounce the words in italics with an emphasis, using verbal stress.
An example for
<i>
could be: "The
Queen Mary
sailed last night". Here, there is no added emphasis or importance on the word "Queen Mary". It is merely indicated that the object in question is not a queen named Mary, but a ship named
Queen Mary
. Another example for
<i>
could be: "The word
the
is an article".
<em>
element is often used to indicate an implicit or explicit contrast.
<p> In HTML 5, what was previously called <em>block-level</em> content is now called <em>flow</em> content. </p>
| 桌面 | 移动 | |||||||||||
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em
|
Chrome 完整支持 1 | Edge 完整支持 12 | Firefox 完整支持 1 | IE 完整支持 Yes | Opera 完整支持 Yes | Safari 完整支持 Yes | WebView Android 完整支持 Yes | Chrome Android 完整支持 Yes | Firefox Android 完整支持 4 | Opera Android 完整支持 Yes | Safari iOS 完整支持 Yes | Samsung Internet Android 完整支持 Yes |
完整支持
