resources/src/mediawiki/mediawiki.confirmCloseWindow.js

   1 ( function ( mw, $ ) {
   2         /**
   3          * @method confirmCloseWindow
   4          * @member mw
   5          *
   6          * Prevent the closing of a window with a confirm message (the onbeforeunload event seems to
   7          * work in most browsers.)
   8          *
   9          * This supersedes any previous onbeforeunload handler. If there was a handler before, it is
  10          * restored when you execute the returned function.
  11          *
  12          *     var allowCloseWindow = mw.confirmCloseWindow();
  13          *     // ... do stuff that can't be interrupted ...
  14          *     allowCloseWindow();
  15          *
  16          * @param {Object} [options]
  17          * @param {string} [options.namespace] Namespace for the event registration
  18          * @param {string} [options.message]
  19          * @param {string} options.message.return The string message to show in the confirm dialog.
  20          * @param {Function} [options.test]
  21          * @param {boolean} [options.test.return=true] Whether to show the dialog to the user.
  22          * @return {Function} Execute this when you want to allow the user to close the window
  23          */
  24         mw.confirmCloseWindow = function ( options ) {
  25                 var savedUnloadHandler,
  26                         mainEventName = 'beforeunload',
  27                         showEventName = 'pageshow';
  28
  29                 options = $.extend( {
  30                         message: mw.message( 'mwe-prevent-close' ).text(),
  31                         test: function () { return true; }
  32                 }, options );
  33
  34                 if ( options.namespace ) {
  35                         mainEventName += '.' + options.namespace;
  36                         showEventName += '.' + options.namespace;
  37                 }
  38
  39                 $( window ).on( mainEventName, function () {
  40                         if ( options.test() ) {
  41                                 // remove the handler while the alert is showing - otherwise breaks caching in Firefox (3?).
  42                                 // but if they continue working on this page, immediately re-register this handler
  43                                 savedUnloadHandler = window.onbeforeunload;
  44                                 window.onbeforeunload = null;
  45                                 setTimeout( function () {
  46                                         window.onbeforeunload = savedUnloadHandler;
  47                                 }, 1 );
  48
  49                                 // show an alert with this message
  50                                 if ( $.isFunction( options.message ) ) {
  51                                         return options.message();
  52                                 } else {
  53                                         return options.message;
  54                                 }
  55                         }
  56                 } ).on( showEventName, function () {
  57                         // Re-add onbeforeunload handler
  58                         if ( !window.onbeforeunload && savedUnloadHandler ) {
  59                                 window.onbeforeunload = savedUnloadHandler;
  60                         }
  61                 } );
  62
  63                 // return the function they can use to stop this
  64                 return function () {
  65                         $( window ).off( mainEventName + ' ' + showEventName );
  66                 };
  67         };
  68 } )( mediaWiki, jQuery );