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