Calling Javascript from an HTML5 build

We have a UE4 scene where we need to send a command to the Google Speech API (it has to be Google because that’s the only one that does arabic). So we need to be able to send a Javascript command from Unreal in an HTML5 build. It looks like UE4.11 supports Javascript commands, but not in HTML5 builds.

Is there a workaround to calling Javascript in HTML5?