Missing external browser declarations and download idl files script does not work

[ApoloApps]

Theres a problem with the current script that you're using. First of all, the urls are not accessible, so ive had to check for the new urls but the thing is when removing the df-panel and other, the script skips some declarations' fields. (Eg: document.hidden and like this there are several more). Fetching the idl from html (index.html is now not used in newer w3c spec pages, instead theyre using index.bs, which cant be read by the script) is not a good idea cause every page has different class names and uses for them. Example is the newer dom spec page, which uses <code class="idl"> and at the end of the page there is a full code block with all the idl code in the page that uses the same class, so the script is also getting it. I've checked and other spec pages use the same class in other places so it would cause incorrect idl files. (and please add indexeddb)

[ApoloApps]

@igoriakovlev sorry for tagging you directly but i think declarations should be updated