you cant,

but you can try this

Code:
<script language="javascript" type="text/javascript">
var defaultWidth = 300;
var defaultHeight = 300;
window.onresize = function (evt) {
  if ((document.all && document.body.offsetWidth >= screen.availWidth)
      || (window.outerWidth && window.outerWidth >= screen.availWidth))
    window.resizeTo(defaultWidth, defaultHeight);
}
</script>
Change defaultWidth and defaultHeight to the default amount