JavaScript silently closes the current page window, compatible with Ie/firefox/chrome

<script type= "Text/javascript" language= "JavaScript" >function FC () {var browsername=navigator.appname; if ( browsername== "Netscape") {       window.open (', ' _parent ', ');      Window.close ();     } else if (browsername== "Microsoft Internet Explorer") {   Window.opener = "Whocares";    Window.close ();     } } </script>
has been tested through, compatible with IE, Google, Firefox needs to be configured:
1. Enter About:config in the Address bar and return, warning confirmation
2, enter "Dom.allow_scripts_to_close_windows" in the filter, double-click to set this value to True
JavaScript silently closes the current page window, compatible with Ie/firefox/chrome