HTML <bdo> Tag
<bdo> tag is used for over-riding the text direction in an HTML document.
This can be useful when displaying right-to-left written text (such as Hebrew, Arabic, Persian, Thaana, Urdu and other languages/scripts that are written from right to left) within left-to-right text (such as English) or vice versa.
<bdo> tag is written as
</bdo> with the relevant text inserted between the start and end tag. The value of the
dir attribute must be either
ltr (but not
auto, which is allowed in other elements).
Basic tag usage
Here's an example using English words written backwards to demonstrate how the tag works.
Here's an example using Persian (a right-to-left language). The first line doesn't use the
<bdo> tag to specify right-to-left text, while the second one does. You can see that by adding
<bdo dir="rtl">, the exclamation mark appears to the left of the phrase.
If the exclamation mark is part of the right-to-left phrase, it should appear to the left of it.
Attributes can be added to an HTML element to provide more information about how the element should appear or behave.
There are 3 kinds of attributes that you can add to your HTML tags: Element-specific, global, and event handler content attributes.
<bdo> element accepts the following attributes.
This table shows the attributes that are specific to the
|dir*||* Although this element has no local attributes, you must use the
This attribute must have the value
The following attributes are standard across all HTML5 elements. Therefore, you can use these attributes with the
<bdo> tag , as well as with all other HTML 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.
Below are the standard HTML5 event handler content attributes.
Again, you can use any of these with the
<bdo> element, as well as any other HTML5 element.
For a full explanation of these attributes, see HTML 5 event handler content attributes.
Differences Between HTML 4 & HTML 5
Here's a template for the
<bdo> tag with all available attributes for the tag (based on HTML5). These are grouped into attribute types, each type separated by a space. In many cases, you will probably only need one or two (if any) attributes. Simply remove the attributes you don't need.
dir global attribute must be specified on this element, with the value
ltr to specify a left-to-right override and with the value
rtl to specify a right-to-left override. The
auto value must not be specified.
Here are the official specifications for the
- HTML5 Specification (W3C)
- HTML Living Standard (WHATWG)
- Current W3C Draft (the next version that is currently being worked on)
- HTML 4 (W3C)
What's the Difference?
W3C creates "snapshot" specifications that don't change once defined. So the HTML5 specification won't change once it becomes an official recommendation. WHATWG on the other hand, develops a "living standard" that is updated on a regular basis. In general, you will probably find that the HTML living standard will be more closely aligned to the current W3C draft than to the HTML5 specification.