using a button in webplayer interface to choose between different background music

hello everybody
so i create a scene with just a cube and a speaker in the project manager
i export it
i use a index.html with iframe
<iframe allowfullscreen src="webplayer.html?load=mybutton.json" width="800" height="500"></iframe>
i create a new button in the webplayer.html and in the webplayer.css

i create a code with a
sound_change_button.addEventListener("mousedown", button_changesound_click, false);

function button_changesound_click(e) {console.log("clicclic");}

ok it works until here
i place in my script
var m_scs = b4w.require("scenes");// console.log(m_scs);
var m_sfx = b4w.require("sfx");

but when i do
var spk = m_sfx.get_object_by_name("Speaker");
or
var spk = b4w.module.sfx.get_object_by_name("Speaker");

i get in my firefox consol
TypeError: m_sfx.get_object_by_name is not a function
or
TypeError: h is not a function

well there is something i do wrong but that?

yeah i have succed
http://blend4web.pagesperso-orange.fr/

Glad to hear it worked for you!