How to get Printable Contents and Non Printable Contents in Javascript

<script language="javascript" type="text/javascript">

function PopPrint() {

var originalContents = document.body.innerHTML;

var prtContent = document.getElementById('<%=Receipt.ClientID %>');

var printContents = prtContent.innerHTML;

document.body.innerHTML = printContents;

window.print();

document.body.innerHTML = originalContents;

}

</script>