Client-side includes is the terminology, but it's not as straight-forward as just including a file. (The link discusses the process, and advises of some pitfalls.)
Essentially, you can attach a javascript file, which includes a function, which uses
document.write to write to the file at the current location.
Easier would be to use an
iframe to include content at a specific point in your document.
A third alternative occurs to me - which is to wait until the document has loaded and use JavaScript to manipulate, and append to, the DOM-body - but there is probably no advantage to this approach compared to the first mentioned method.
If you decide to pursue a copy/paste approach you could consider adding specific comments at certain points in the files and use ST's Find/Replace in Files feature (or some other file utility) to replace (or append after) the comments in
one fell swoop. I think you would need to plan this carefully, and I would consider something like this:
<!-- include:navigation.html -->
<!-- include:end -->so that you could insert the text between these comments and repeat the process at a later-stage if you needed to. Andy.
"I'm here to save your life. But if I'm going to do that, I'll need total uninanonynymity." Me Myself & Irene.