How to Close The Pop Up Window in JavaScript

<script type="text/javascript">

function ClosePopup(DivPopup){
     document.getElementById("<%=ID.ClientID %>").value = ""
     document.getElementById("<%= ID .ClientID %>").value = ""
     document.getElementById("<%= ID .ClientID %>").value = ""
     document.getElementById(DivPopup).style.display = 'none';
 }

 </script>