javascript - Identifying which element invoked the event -

i have following html code

<input type="button"  id ="b1" value="click me" onclick="msg()" /> <input type="button" id="b2"   value="click me" onclick="msg()" />

now in javascript want identify whether button 1 clicked or button 2. how can it?

if change inline handler use .call() method, setting context of function this:

<input type="button"  id ="b1" value="click me" onclick="msg.call( )" />

...then in function, this represent 1 received event.

function msg() {     alert( this.id ); }

otherwise, pass this argument:

<input type="button"  id ="b1" value="click me" onclick="msg( )" />

...and reference argument:

function msg( elem ) {     alert( elem.id ); }

TY