HTML <source> Tag

The HTML <source> tag is used to specify multiple media resources on media elements (such as the <audio> and <video> elements).

The <source> tag allows you to specify alternative video and audio files which the browser may choose from based on its media type or codec support.


The <source> tag is written as <source src="" type=""> (no end tag) with the URL of the media listed between the double quotes of the src attribute. The type attribute can be used to specify the type of the media resource. This helps the browser determine whether or not it can play the media resource before downloading it.

Like this:


Basic tag usage

The codecs Parameter

You might also need to provide the codecs parameter to specify exactly how the resource has been encoded.

Like this:

For examples of values that can be used with the codecs parameter, see the official specifications (listed below).


Attributes can be added to an HTML element to provide more information about how the element should appear or behave.

The <source> element accepts the following attributes.

srcSpecifies the location of the audio/video file. Its value must be the URL of an audio/video file.
typeSpecifies the type of the embedded content. If specified, the value must be a MIME type.

mediaSpecifies the type of media resource, so the browser can determine whether it can play it or not. If not, it can choose not to download it. If specified, the value must be a valid media query.

Global Attributes

The following attributes are standard across all HTML elements. Therefore, you can use these attributes with the <source> tag , as well as with all other HTML tags.

For a full explanation of these attributes, see HTML 5 global attributes.

Event Handlers

Event handler content attributes enable you to invoke a script from within your HTML. The script is invoked when a certain "event" occurs. Each event handler content attribute deals with a different event.

Most event handler content attributes can be used on all HTML elements, but some event handlers have specific rules around when they can be used and which elements they are applicable to.

For more detail, see HTML event handler content attributes.