function wopen(url, w_alt, w_width, w_height){
gWindow = window.open(url,"popup_window","menubar=no,toolbar=no,scrollbars=no,status=yes,width="+w_width+",height="+w_height+",top=20,left=20");
gWindow.focus();
if (gWindow){
gWindow.document.open();
gWindow.document.write(""+w_alt+"");
gWindow.document.close();
}
}