Is there a reasonable way to search standards for programming and markup languages (specifically, C, C++, Java, JavaScript, (X)HTML)? Standard libraries tend to be well-documented and easy to access, but when looking for information on the basics of a language I always have trouble, and end up getting most of my information second-hand from tutorials. That's not all bad, since tutorials often point out gotchas (such as even though this is in the standard, it doesn't work in Internet Explorer) but tutorials are sometimes wrong and often don't cover more obscure areas.
I assume you are looking for a syntax reference, as opposed to a standard. The standard is precise but probably too low level for what you really want. A syntax reference will show you the language constructs for looping, selection etc. There are some exceptions such as (X)HTML which is a markup language as opposed to a programming language. Markup language standards documents tend to be more useful from the reference perspective.
For example look at the Visual C++ Language Reference and compare it to a version of the standard.
There is really only one way to get information from a standard: read the standard.
If the standard is too hard to read (and a lot of them are), then maybe the standards folks have created (non-normative) introduction or tutorial documents. But they are not the standard. Very occasionally, someone produces an "annotated" version of a specification that offers simplified explanations. These are very useful, but once again they are not the standard.
If a standard is available in machine readable / searchable form, document search on suitably chosen keywords can often point to the relevant part(s) of the documents. But you have to read and understand the text. There are no tools around (that I'm aware of) that can accurately translate the (often abstruse) technical details of a standard into something that "normal people" can read easily.
This is why we label people who are intimately familiar with particular standards "standards lawyers" or "language lawyers". It is analogous to lawyers and judges reading/writing legal documents.
For (X)HTML and the DOM, the standards are handled by the W3C. But as you know, browsers don't exactly follow the standards. For an exhaustive resource on browser issues there's nothing better than the quirksmode compatibility tables.