I embed javascript port into my emscripten application. mp_js_do_str works fine in my c code.
And that pyexec_file invoke a python file is fine too. i.e. upy works in web application. But The python file can't "import" another module which is also a python file in the same directory.
I test it in emscripten MEMFS root directory "/".

This is the gist below:

	FILE* fp = NULL;
	fp = fopen("t2.py", "w");
	fprintf(fp, "import woxiao\nwoxiao.HUDPrint(\"print by t2.py\")\n");
	fclose(fp);

	fp = fopen("t1.py", "w");
	//fprintf(fp, "import woxiao\nwoxiao.HUDPrint(\"print by t1.py\")\ntry:\nimport t2\nwoxiao.HUDPrint(\"+ import t2 done\")\npass\nexcept ImportError:\nwoxiao.HUDPrint(\"- import t2 failed\")\n");
	fprintf(fp, "import woxiao\nwoxiao.HUDPrint(\"print by t1.py\")\nimport t2\n");
	fclose(fp);

	//pyexec_file ("t2.py");  //works fine
	pyexec_file ("t1.py");  // can't import t2

ps. "woxiao.HUDPrint" is just a debug print function in my own "woxiao" module which is extended in my C code. And it works fine.