When I tried using QSslSocket to download a web page, it crashes with this message:

 
06:56:30.762 To use dlopen, you need to use Emscripten's linking support, see https://github.com/emscripten-core/emscripten/wiki/Linking qtloader.js:372:25
06:56:30.762 To use dlopen, you need to use Emscripten's linking support, see https://github.com/emscripten-core/emscripten/wiki/Linking qtloader.js:382:25
06:56:30.763
uncaught exception: abort("To use dlopen, you need to use Emscripten's linking support, see https://github.com/emscripten-core/emscripten/wiki/Linking"). Build with -s ASSERTIONS=1 for more info.

Qt was configured using openssl -openssl-l-inked and static build.

Appears that -openssl-linked is failing:

OpenSSL ................................ yes
Qt directly linked to OpenSSL ........ no