lib/dojo/_base/unload.js.uncompressed.js

   1 define("dojo/_base/unload", ["./kernel", "./connect"], function(dojo, connect) {
   2         // module:
   3         //              dojo/unload
   4         // summary:
   5         //              This module contains the document and window unload detection API.
   6
   7         var win = window;
   8
   9         /*=====
  10                 dojo.windowUnloaded = function(){
  11                         // summary:
  12                         //              signal fired by impending window destruction. You may use
  13                         //              dojo.addOnWindowUnload() to register a listener for this
  14                         //              event. NOTE: if you wish to dojo.connect() to this method
  15                         //              to perform page/application cleanup, be aware that this
  16                         //              event WILL NOT fire if no handler has been registered with
  17                         //              dojo.addOnWindowUnload. This behavior started in Dojo 1.3.
  18                         //              Previous versions always triggered dojo.windowUnloaded. See
  19                         //              dojo.addOnWindowUnload for more info.
  20                 };
  21         =====*/
  22
  23         dojo.addOnWindowUnload = function(/*Object?|Function?*/obj, /*String|Function?*/functionName){
  24                 // summary:
  25                 //              registers a function to be triggered when window.onunload
  26                 //              fires.
  27                 //      description:
  28                 //              The first time that addOnWindowUnload is called Dojo
  29                 //              will register a page listener to trigger your unload
  30                 //              handler with. Note that registering these handlers may
  31                 //              destory "fastback" page caching in browsers that support
  32                 //              it. Be careful trying to modify the DOM or access
  33                 //              JavaScript properties during this phase of page unloading:
  34                 //              they may not always be available. Consider
  35                 //              dojo.addOnUnload() if you need to modify the DOM or do
  36                 //              heavy JavaScript work since it fires at the eqivalent of
  37                 //              the page's "onbeforeunload" event.
  38                 // example:
  39                 //      | dojo.addOnWindowUnload(functionPointer)
  40                 //      | dojo.addOnWindowUnload(object, "functionName");
  41                 //      | dojo.addOnWindowUnload(object, function(){ /* ... */});
  42
  43                 if (!dojo.windowUnloaded) {
  44                         connect.connect(win, "unload", (dojo.windowUnloaded= function(){}));
  45                 }
  46                 connect.connect(win, "unload", obj, functionName);
  47         };
  48
  49         dojo.addOnUnload = function(/*Object?|Function?*/obj, /*String|Function?*/functionName){
  50                 // summary:
  51                 //              registers a function to be triggered when the page unloads.
  52                 //      description:
  53                 //              The first time that addOnUnload is called Dojo will
  54                 //              register a page listener to trigger your unload handler
  55                 //              with.
  56                 //
  57                 //              In a browser enviroment, the functions will be triggered
  58                 //              during the window.onbeforeunload event. Be careful of doing
  59                 //              too much work in an unload handler. onbeforeunload can be
  60                 //              triggered if a link to download a file is clicked, or if
  61                 //              the link is a javascript: link. In these cases, the
  62                 //              onbeforeunload event fires, but the document is not
  63                 //              actually destroyed. So be careful about doing destructive
  64                 //              operations in a dojo.addOnUnload callback.
  65                 //
  66                 //              Further note that calling dojo.addOnUnload will prevent
  67                 //              browsers from using a "fast back" cache to make page
  68                 //              loading via back button instantaneous.
  69                 // example:
  70                 //      | dojo.addOnUnload(functionPointer)
  71                 //      | dojo.addOnUnload(object, "functionName")
  72                 //      | dojo.addOnUnload(object, function(){ /* ... */});
  73
  74                 connect.connect(win, "beforeunload", obj, functionName);
  75         };
  76
  77         return {
  78                 addOnWindowUnload: dojo.addOnWindowUnload,
  79                 addOnUnload: dojo.addOnUnload
  80         };
  81 });