resources/src/mediawiki/mediawiki.confirmCloseWindow.js

   1 /* jshint devel: true */
   2 ( function ( mw, $ ) {
   3         /**
   4          * @method confirmCloseWindow
   5          * @member mw
   6          *
   7          * Prevent the closing of a window with a confirm message (the onbeforeunload event seems to
   8          * work in most browsers.)
   9          *
  10          * This supersedes any previous onbeforeunload handler. If there was a handler before, it is
  11          * restored when you execute the returned release() function.
  12          *
  13          *     var allowCloseWindow = mw.confirmCloseWindow();
  14          *     // ... do stuff that can't be interrupted ...
  15          *     allowCloseWindow.release();
  16          *
  17          * The second function returned is a trigger function to trigger the check and an alert
  18          * window manually, e.g.:
  19          *
  20          *     var allowCloseWindow = mw.confirmCloseWindow();
  21          *     // ... do stuff that can't be interrupted ...
  22          *     if ( allowCloseWindow.trigger() ) {
  23          *         // don't do anything (e.g. destroy the input field)
  24          *     } else {
  25          *         // do whatever you wanted to do
  26          *     }
  27          *
  28          * @param {Object} [options]
  29          * @param {string} [options.namespace] Namespace for the event registration
  30          * @param {string} [options.message]
  31          * @param {string} options.message.return The string message to show in the confirm dialog.
  32          * @param {Function} [options.test]
  33          * @param {boolean} [options.test.return=true] Whether to show the dialog to the user.
  34          * @return {Object} An object of functions to work with this module
  35          */
  36         mw.confirmCloseWindow = function ( options ) {
  37                 var savedUnloadHandler,
  38                         mainEventName = 'beforeunload',
  39                         showEventName = 'pageshow',
  40                         message;
  41
  42                 options = $.extend( {
  43                         message: mw.message( 'mwe-prevent-close' ).text(),
  44                         test: function () { return true; }
  45                 }, options );
  46
  47                 if ( options.namespace ) {
  48                         mainEventName += '.' + options.namespace;
  49                         showEventName += '.' + options.namespace;
  50                 }
  51
  52                 if ( $.isFunction( options.message ) ) {
  53                         message = options.message();
  54                 } else {
  55                         message = options.message;
  56                 }
  57
  58                 $( window ).on( mainEventName, function () {
  59                         if ( options.test() ) {
  60                                 // remove the handler while the alert is showing - otherwise breaks caching in Firefox (3?).
  61                                 // but if they continue working on this page, immediately re-register this handler
  62                                 savedUnloadHandler = window.onbeforeunload;
  63                                 window.onbeforeunload = null;
  64                                 setTimeout( function () {
  65                                         window.onbeforeunload = savedUnloadHandler;
  66                                 }, 1 );
  67
  68                                 // show an alert with this message
  69                                 return message;
  70                         }
  71                 } ).on( showEventName, function () {
  72                         // Re-add onbeforeunload handler
  73                         if ( !window.onbeforeunload && savedUnloadHandler ) {
  74                                 window.onbeforeunload = savedUnloadHandler;
  75                         }
  76                 } );
  77
  78                 /**
  79                  * Return the object with functions to release and manually trigger the confirm alert
  80                  *
  81                  * @ignore
  82                  */
  83                 return {
  84                         /**
  85                          * Remove all event listeners and don't show an alert anymore, if the user wants to leave
  86                          * the page.
  87                          *
  88                          * @ignore
  89                          */
  90                         release: function () {
  91                                 $( window ).off( mainEventName + ' ' + showEventName );
  92                         },
  93                         /**
  94                          * Trigger the module's function manually: Check, if options.test() returns true and show
  95                          * an alert to the user if he/she want to leave this page. Returns false, if options.test() returns
  96                          * false or the user cancelled the alert window (~don't leave the page), true otherwise.
  97                          *
  98                          * @ignore
  99                          * @return {boolean}
 100                          */
 101                         trigger: function () {
 102                                 // use confirm to show the message to the user (if options.text() is true)
 103                                 if ( options.test() && !confirm( message ) ) {
 104                                         // the user want to keep the actual page
 105                                         return false;
 106                                 }
 107                                 // otherwise return true
 108                                 return true;
 109                         }
 110                 };
 111         };
 112 } )( mediaWiki, jQuery );