> (Website:) SpiderBasic is new web client-side programming language based on established BASIC rules. Its allows development of very complex, windowed based web applications, including mobile app for iOS and Android [...] SpiderBasic is a compiler which generates optimized JavaScript
It is a BASIC based language (and tools - e.g. an IDE, if you wish) that compiles into Javascript.
«windowed based web applications»: since the original PureBasic, the language and tools that compiled to native executables, (also) allowed to build windowed applications (complete original GUIs), SpiderBasic, the product in the same family for the Web, also allows to have windows and desktop-like controls in a webpage (optionally).
> the docs ... a page of links to single pages without navigation to the rest of the docs
??? The online documentation is hypertextual, each page linking to the relevant other pages - as it should be. In real practice, documentation is directly accessible from the IDE (optional but a real asset).