HTML
<source>
element
指定多媒体资源为
<picture>
，
<audio>
元素，或
<video>
元素。
It is an empty element, meaning that it has no content and does not have a closing tag. It is commonly used to offer the same media content in multiple file formats in order to provide compatibility with a broad range of browsers given their differing support for
image file formats
and
media file formats
.
The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.
| 内容类别 | None. |
|---|---|
| 准许内容 | None, it is an empty element . |
| Tag omission | It must have a start tag, but must not have an end tag. |
| Permitted parents |
A media element—
<audio>
or
<video>
—and it must be placed before any
flow content
or
<track>
元素。
|
| Implicit ARIA role | 无对应角色 |
| Permitted ARIA roles |
No
role
permitted
|
| DOM 接口 |
HTMLSourceElement
|
此元素包括 全局属性 .
media
<picture>
元素。
sizes
Is a list of source sizes that describes the final rendered width of the image represented by the source. Each source size consists of a comma-separated list of media condition-length pairs. This information is used by the browser to determine, before laying the page out, which image defined in
srcset
to use. Please note that
sizes
will have its effect only if width dimension descriptors are provided with
srcset
instead of pixel ratio values (200w instead of 2x for example).
sizes
attribute has an effect only when the
<source>
element is the direct child of a
<picture>
元素。
src
<audio>
and
<video>
, address of the media resource. The value of this attribute is ignored when the
<source>
element is placed inside a
<picture>
元素。
srcset
A list of one or more strings separated by commas indicating a set of possible images represented by the source for the browser to use. Each string is composed of:
"w"
，譬如
300w
. The default value, if missing, is the infinity.
"x"
. The default value, if missing, is
1x
.
Each string in the list must have at least a width descriptor or a pixel density descriptor to be valid. Among the list, there must be only one string containing the same tuple of width descriptor and pixel density descriptor. The browser chooses the most adequate image to display at a given point of time.
srcset
attribute has an effect only when the
<source>
element is the direct child of a
<picture>
元素。
type
codecs
参数
.
若
type
attribute isn't specified, the media's type is retrieved from the server and checked to see if the user agent can handle it; if it can't be rendered, the next
<source>
is checked. If the
type
attribute is specified, it's compared against the types the user agent can present, and if it's not recognized, the server doesn't even get queried; instead, the next
<source>
element is checked at once.
When used in the context of a
<picture>
element, the browser will fall back to using the image specified by the
<picture>
元素的
<img>
child if it is unable to find a suitable image to use after examing every provided
<source>
.
<source>
element is an
empty element (or void element)
, which means that it not only has no content but also has no closing tag. That is, you
never
use "
</source>
" in your HTML.
For information about image formats supported by web browsers and guidance on selecting appropriate formats to use, see our Image file type and format guide on the web. For details on the video and audio media types, you can use, see the Guide to media types formats used on the web .
This example demonstrates how to offer a video in Ogg format for users whose browsers support Ogg format, and a QuickTime format video for users whose browsers support that. If the
audio
or
视频
element is not supported by the browser, a notice is displayed instead. If the browser supports the element but does not support any of the specified formats, an
error
event is raised and the default media controls (if enabled) will indicate an error. Be sure to reference our
guide to media types and formats on the web
for details on what media file formats you can use and how well they're supported by browsers.
<video controls> <source src="foo.webm" type="video/webm"> <source src="foo.ogg" type="video/ogg"> <source src="foo.mov" type="video/quicktime"> I'm sorry; your browser doesn't support HTML5 video. </video>
For more examples, the learning area article Video and audio content is a great resource.
In this example, two
<source>
elements are included within the
<picture>
, providing versions of an image to use when the available space exceeds certain widths. If the available width is less than the smaller of these widths, the user agent will fall back to the image given by the
<img>
元素。
<picture> <source srcset="mdn-logo-wide.png" media="(min-width: 800px)"> <source srcset="mdn-logo-medium.png" media="(min-width: 600px)"> <img src="mdn-logo-narrow.png" alt="MDN Web Docs"> </picture>
With the
<picture>
element, you must always include an
<
img
>
with a fallback image, with an
alt
attribute to ensure accessibility (unless the image is an irrelevant background decorative image).
| 规范 | 状态 | 注释 |
|---|---|---|
|
HTML 实时标准
The definition of '<source>' in that specification. |
实时标准 |
| 桌面 | 移动 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
source
|
Chrome 完整支持 Yes | Edge 完整支持 12 |
Firefox
完整支持
3.5
注意事项
|
IE 完整支持 9 | 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
注意事项
|
Opera Android ? | Safari iOS 完整支持 Yes | Samsung Internet Android 完整支持 Yes |
media
|
Chrome 完整支持 Yes | Edge 完整支持 12 | Firefox 完整支持 15 | IE 完整支持 9 | 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 15 | Opera Android ? | Safari iOS 完整支持 Yes | Samsung Internet Android 完整支持 Yes |
sizes
|
Chrome 完整支持 Yes | Edge 完整支持 ≤18 |
Firefox
完整支持
38
|
IE ? | Opera 完整支持 Yes |
Safari
完整支持
9
|
WebView Android 完整支持 Yes | Chrome Android 完整支持 Yes |
Firefox Android
完整支持
38
|
Opera Android ? |
Safari iOS
完整支持
9
|
Samsung Internet Android 完整支持 Yes |
src
|
Chrome 完整支持 Yes | Edge 完整支持 12 | Firefox 完整支持 3.5 | IE 完整支持 9 | 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 ? | Safari iOS 完整支持 Yes | Samsung Internet Android 完整支持 Yes |
srcset
|
Chrome 完整支持 Yes | Edge 完整支持 ≤18 |
Firefox
完整支持
38
|
IE ? | Opera 完整支持 Yes |
Safari
完整支持
9
|
WebView Android 完整支持 Yes | Chrome Android 完整支持 Yes |
Firefox Android
完整支持
38
|
Opera Android ? |
Safari iOS
完整支持
9
|
Samsung Internet Android 完整支持 Yes |
type
|
Chrome 完整支持 Yes | Edge 完整支持 12 | Firefox 完整支持 3.5 | IE 完整支持 9 | 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 ? | Safari iOS 完整支持 Yes | Samsung Internet Android 完整支持 Yes |
完整支持
兼容性未知
见实现注意事项。
用户必须明确启用此特征。
<picture>
element
<audio>
element
<video>
element