Confirm Box in JavaScript

JavaScript Code:

<script type="text/javascript">

function showBox()

{

var r=confirm("Press to button");

if (r==true)

  {

  alert("You pressed OK!");

  }

else

  {

  alert("You pressed Cancel!");

  }

}

</script>

HTML Code:

<input type="btn_Sow" onclick="showBox()" value="Show!" />