VS 2010 - Playing Audio Clip On Button Event

i want to play a sound file using following code in my aspx page

<asp:Button ID="btnPlay" runat="server" Text="Play" />

<script type="text/javascript">
function EvalSound(soundobj) {
var thissound = document.getElementById(soundobj);
thissound.Play();
}
</script>
<embed src="doorbell-1.wav" autostart="false" width="1" height="1" id="sound1" enablejavascript="true" >
</embed>

and then calls following code on my aspx.vb code page on page_load

btnPlay.Attributes.Add("onclick", "return EvalSound('sound1');")

but dinot hear any sound

where if i use html button instead it works fine like this

<input type="button" id="btnPlay" onclick="EvalSound('sound1');"/>