HTML 5 <eventsource> Tag

Since this article was written, this tag has now been removed from the HTML5 specification (which is still in draft status at time of writing). Rather than remove this article altogether, I have decided to keep it here for reference.

The HTML <eventsource> tag represents a target for events generated by a remote server.

Note that the <eventsource> element is an empty element (no closing tag is used).

The <eventsource> tag was introduced in HTML 5.


HTML tags can contain one or more attributes. Attributes are added to a tag to provide the browser with more information about how the tag should appear or behave. Attributes consist of a name and a value separated by an equals (=) sign, with the value surrounded by double quotes. Here's an example, style="color:black;".

There are 3 kinds of attributes that you can add to your HTML tags: Element-specific, global, and event handler content attributes.

The attributes that you can add to this tag are listed below.

Element-Specific Attributes

The following table shows the attributes that are specific to this tag/element.

srcSpecifies the server resource that generates the event/s. The value must be a valid URL identifying a resource that uses the text/event-stream format.

Global Attributes

The following attributes are standard across all HTML 5 tags.

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

Event Handler Content Attributes

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.

Here are the standard HTML 5 event handler content attributes.

For a full explanation of these attributes, see HTML 5 event handler content attributes.