Breaking validation from bug 22942 into its own bug. This is only about validation with DTDs. If you want schema validation that is a different bug.
Note that we have identified some needs (for example Web Services, editor) which would be easier to implement if the validation was done in the content model (compared to validation done during the actual parse, like Xerces(?) does).
Note that (IMHO) this should most definitely not be done on-load. We don't want to be validating any document we open, wellformedness checking is quite enough.
Is this basically requesting a scriptable API to take a DOM and validate it, which extensions or GRE apps such as Composer can then leverage to implement validation services?
Would it be possible to handle the processing of named entities in the external DTD? It doesn't seem to be happening at the moment.
Firefox doesn't appear to validate illegal character escapes right now either. Is that part of this bug as well? (e.g.  is considered "standards compliance" even though any real XML parser would reject it in a snap.)
What's wrong with  ?
(In reply to comment #5) > (e.g.  is considered "standards compliance" even though any real XML parser > would reject it in a snap.) WorksForMe : "XML Parsing Error: reference to invalid character number"
Cross-posting on relevant bug pages: For this bug, and a number of other associated bugs (Bug 204102, Bug 267350, Bug 22942, and to a lesser extent Bug 196355), I've started a pledge drive at http://pledgie.com/campaigns/7732 to try to hire a developer(s) who can work with the Mozilla devs (if they are ineligible themselves) to get these long-standing and niche but important-to-XML-users bugs fixed. Feel free to make a pledge to donate toward these fixes or, if you are a developer, make a bid in the comments there to offer to fix, in conjunction with Mozilla devs, this or any of the other aforementioned XML-related bugs/feature requests. (If we can get enough momentum, Bug 234485, Bug 98413, Bug 275196, and Bug 94270 might be also nice candidates to get addressed too, but I've started with the (single-point-of-failure-causing) DTD issues.)