Execute function when play button is clicked in html5 audio player

Is it possible to detect when the play button in the html5 audio player is clicked? For example:

Code:

---

<audio controls>
    <source src="music.mp3"/>
    <source src="music.ogg" />
</audio>
....
....
$('playbutton').on('click', function(e){
    //some functions
});

---

http://www.quackit.com/html_5/tags/html_audio_tag.cfm

Code:

---

$(audio)[0].onplay= function(e){
    //some functions
};

---

I tried this but it doesn't do anything, no alert is produced when I click play button:

Code:

---

$(audio)[0].onplay= function(e){
    alert('playing');
};
...
...
<audio controls>
    <source src="music.mp3"/>
    <source src="music.ogg" />
</audio>

---

What is the [0] for?

oops:

Code:

---

$('audio')[0].onplay= function(e){
    //some functions
};

---