Static Html Content Reuse

For logistical and legacy reasons, there are certain web pages in our org we cannot use SHTML or server-side content sharing (per reuse & content OnceAndOnlyOnce), such as "include" statements. The HTML standard has no client-side "include" equivalency, unfortunately.

Doing it via JavaScript (JS) is one possibility, but it's often awkward to code that way, search engines often skip JS-generated content, and it can create ADA-compliance problems per ADA reader software. iFrames have given us sizing problems and other side-effects.

Has anybody found a decent solution, or wish to offer recommendations? It's one of those things that feels like it could or should be simple, but is not.

[How about static-site compilers, like http://jekyllrb.com/ ? Common content can be included at compile-time, rather than on the fly when pages are accessed. -DavidMcLean?]

That wouldn't work in our circumstance.