Is there something similar to Link to a PDF File on a Specific Page for webpages.
A little unsure what you mean with the general term “webpages” as a typical webpage is not split up into pages like a sequential pdf document. But for tiddlers, there is of course the permalink to tiddlers and within tiddlers you can use anchor links.
Depending on the design of the webpage there can be many other ways to specify where to navigate to.
Well you can link to a specific tiddler in a tiddlywiki but if your PDF is a seperate file you will need to look at the command line doco for your PDF reader app. I expect they will be similar to Mohammad’s example at the link you shared.
If crafting links to webpages you need to look at the HTML anchors and link standards.
For annotating PDFs as local files, I have found a method using tiddlyclip where on clicking the annotation links the corresponding page in the pdf will open. For the time being, it works only for text, not images. See these two discussion - 1 and 2.
In this post, I was asking for something similar for webpages.