Moving to following questions automatically/playing sound

I am developing an experiment for academic purposes. I have to questions.

1) I want to set automatic auto-advance, which I found out how to on this link.
I added the following code to the “Edit Java Script Question” box. Now I would like to make “forward” button disappear. Would any ne be able to tell me how to do so?

Qualtrics.SurveyEngine.addOnload(function()
{
var that = this;
this.questionclick = function(event,element){
if (element.type == 'radio') {
that.clickNextButton();
}
}
});

2) I would also like a sound to be played as soon as the page is loaded. I did so by adding the following line inside my "Qualtrics.SurveyEngine.addOnload"

document.getElementById("1_2_3").play();

I also added the following in the HTML view of the question:

<audio>
<audio id="1_2_3" src="the_link_to_my_audio_file_in_qualtrics_library">
</audio>

However, when I preview the question, there is a weird echo. It seems that that file is being played twice! How can I fix this?