<button id="3" onClick="reply_click(this.id)">B3</button>
<script type="text/javascript">
function reply_click(clicked_id)
{
alert(clicked_id);
}
</script>//JavaScript
document.querySelectorAll('div').forEach((e) => {
e.onclick = (e) => console.log(e.currentTarget.id);
});<button id="1" onClick="reply_click(this.id)">B1</button>
<button id="2" onClick="reply_click(this.id)">B2</button>
<button id="3" onClick="reply_click(this.id)">B3</button>
<script type="text/javascript">
function reply_click(clicked_id)
{
alert(clicked_id);
}
</script>