function popup(url,width,height,args){
	if (!width) width = 500;
	if (!height) height = 400;
	if (!args) {
		args = 'width=' + width + ',height=' + height + ',resizable=yes,toolbars=0,toolbar=0,menubar=0,scrollbars=yes,left=0,top=20';
	} else {
		args = 'width=' + width + ',height=' + height + ',' + args;
	}
	var name = 'popupwin';
	window.open(url,name,args);
	window.open(url,name,args).focus();
	window.open(url,name,args).location = url;
}