function popupwindow(argURL,width,height,scrollbar,resize) {

	var screenw = screen.availWidth;
	var screenh = screen.availHeight;

	var leftPos = (screenw-width)/2; 
	var topPos = (screenh-height)/2;

	var agt=navigator.userAgent.toLowerCase();

	var is_major = parseInt(navigator.appVersion);
	var is_minor = parseFloat(navigator.appVersion);

	var is_nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1)
		&& (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1)
		&& (agt.indexOf('webtv')==-1));

	var is_ie   = (agt.indexOf("msie") != -1);
	var is_ie3  = (is_ie && (is_major < 4));
	var is_ie4  = (is_ie && (is_major == 4) && (agt.indexOf("msie 5")==-1) );
	var is_ie5up  = (is_ie  && !is_ie3 && !is_ie4);

	var is_mac    = (agt.indexOf("mac")!=-1);

	if (is_mac)
	{
	displaypopup = window.open(argURL,'Display','resizable='+resize+',scrollbars='+scrollbar+',width='+width+',height='+height+',left='+leftPos+',top='+topPos+',toolbar=yes');
	}
	else if (!is_nav && !is_ie5up)
	{
	displaypopup = window.open(argURL,'Display','resizable='+resize+',scrollbars='+scrollbar+',width='+width+',height='+height+',left='+leftPos+',top='+topPos+',toolbar=yes');
	}
	else
	{
	displaypopup = window.open("",'Display','resizable='+resize+',scrollbars='+scrollbar+',width='+width+',height='+height+',left='+leftPos+',top='+topPos+',toolbar=yes');
	displaypopup.close();
	displaypopup = window.open(argURL,'Display','resizable='+resize+',scrollbars='+scrollbar+',width='+width+',height='+height+',left='+leftPos+',top='+topPos+',toolbar=yes');
	displaypopup.focus();
	}
}