User Agent Support

Any user can access a longdesc by using a user agent that supports it. Recent research finds that modern screen readers have good support for the longdesc attribute. A collection of tools that provide support for longdesc exists for those that need or require that support. Users who want to access long descriptions supplied via longdesc, whether they are sighted or not, have a choice of options to do so. The claim that longdesc isn't exposed to some users is outweighed by the concrete examples of it being exposed in accessible ways and is as ludicrous as suggesting that the <img> element should be removed from HTML5 because its graphic contents cannot be disclosed to users who elect to use Lynx or similar.

On March 11, 2011, professional content producers at the Digital Image and Graphic Resources for Accessible Materials Center (DIAGRAM) addressed longdesc support for other users. Their testimony states:

features developed to help people with specific disabilities also assist other users, and this is true for long image descriptions. Today, for example, Firefox and Opera allow the user to open a context menu over an image and choose to see the long description on the screen, if @longdesc is included with the image. This is an excellent tool for assisting sighted students with learning disabilities who need textual reinforcement when deciphering the contents of a complicated image. Also, as image descriptions become more widely used, it is expected that search engines can take advantage of descriptions in locating relevant images.

Growth in User Agent Support

Since March 11, 2011 user agent implementation has grown. The following examples clearly demonstrate this and how longdesc is machine readable.


The Zero Edit/Obsolete longdesc proposal inaccurately states,

To be successful longdesc needs to have an activation mechanism as easy and intuitive to use as a normal link, which is probably impossible.

It is not impossible. A new longdesk FireFox extension has been developed that adds a link to the longdesc under images that provides one. It makes the longdesc activation easy and intuitive for sighted users who wish access.


For those who would like an indication of when longdescs are available on a page without interfering with page design, a new TellMeMore Opera extension has been developed. It respects visual design and does not force an on-page visual encumbrance. Instead it provides an icon in the chrome to indicate when descriptions exist. Then, upon activating the icon, the user is presented with a popup containing a list of all descriptions available along with their thumbnail images.

Scripted Implementations

New direct replacement functionality has been provided via a scripted implementation. easyALBUM utilizes programmatic determinability as evidenced in several recent photo albums.

Long Description Favelet

A longdesc favelet by James Thatcher first announces the number of images on a page that has longdesc attributes. Then it highlights each image on the page that has a longdesc and provides on-screen text links to each corresponding description. It provides universal functionality of longdesc in browsers such as Chrome, FireFox, Internet Explorer, and Safari. For the functional favelet drag longdesc to your bookmarks.

The Future and User Agent Support

The Zero Edit/Obsolete longdesc Change Proposal fails to provide any evidence that it would be difficult or impossible for user agents to identify and make good use of longdesc. In fact, a FireFox browser vendor responded to a question asking "Would it be possible to make longdesc a global attribute?" by saying, " This is software, anything is possible".

On May 5, 2012, HTML Co-Chair, Maciej Stachowiak stated,

if a UA can give a better experience i think they should be encouraged to try

To help browser vendors in this effort in the future, new text has been specified for the 10.6.1 rendering section. which illustrates how longdesc can be made discoverable. It will encouraged to them to improve support. As Anne van Kesteren has said, examples in the specification serve as an incentive to vendors:

It's an incentive to get the software fixed.