When I hit the submit button, the result are display on a new page. how do I force it to stay on the same page, here's my code.

Code:
<HTML>
<HEAD>
<TITLE>Test Input</TITLE>

<script type="text/javascript">
function addtext() {
   var newtext = document.myform.inputbox.value;
   document.writeln(newtext);
}
</script>

</HEAD>

<BODY>

<FORM NAME="myform">Enter something in the box: <BR>
<INPUT TYPE="text" NAME="inputbox" VALUE="">
<INPUT TYPE="button" NAME="button" Value="Check" onClick="addtext()">
</FORM>


</BODY>
</HTML>
any comments or suggestions would be greatly appreciated.