The custodian of the DOM is the [[World Wide Web Consortium]] (W3C). The current DOM specification is Level 2. Level 1 specification allowed for [[navigation]] of an HTML or XML document and to manipulate content. Level 2 came up with XML [[Namespace]] support, filtered views and events. Level 3 specification is ([[as of 2003]]) a working draft and still under development at the W3C.
A different DOM implementation from [[Microsoft]] has led to [[inter-operability]] problems for web browsers.
As Microsoft's [[Internet Explorer]] browser is, as of [[2005]], the de-facto standard web browser, this poses real problems for the developers of more standards-compliant browsers such as [[Mozilla]]. If they adopt the Microsoft extensions to the DOM, they risk losing any [[credibility]] in their calls for web-sites to become [[standards-compliant]], and if they do not, they risk alienating their users by losing much or all of the [[content]] of web-sites which use the non-standard [[extension (computing)|extension]]s. Cynics regard this as another case of Microsoft applying [[embrace, extend and extinguish]] tactics. This could be considered ironic, as both Microsoft and [[Netscape]] were guilty of supplying non-standard features in an arms-race for standards control, and Mozilla was born out of a Netscape initiative.
The general consensus appears to be that this will only change if new standards-compliant browsers gain a significant market-share on the Web, thus making the use of non-standard extensions a commercial problem for the authors of non-standards-compliant websites.
Internet Explorer 7.0 is rumoured to likely be more standards-compliant in its implementation of the DOM, but is unlikely to pull support for the current proprietary DOM extensions.
