adding commenting/readability to initialize()

git-svn-id: http://svn.openlayers.org/trunk/openlayers@864 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Events.js

@@ -28,6 +28,7 @@ OpenLayers.Events.prototype = {
     /** @type Array: list of support application events */
     eventTypes: null,
 
+
     /**
      * @constructor 
      * 
@@ -37,31 +38,41 @@ OpenLayers.Events.prototype = {
      * @param {Array} eventTypes Array of custom application events
      */
     initialize: function (object, div, eventTypes) {
-        this.listeners  = {};
         this.object     = object;
         this.div        = div;
         this.eventTypes = eventTypes;
 
-        if (eventTypes) {
+        this.listeners  = new Object();
+
+        // if eventTypes is specified, create a listeners list for each 
+        // custom application event.
+        if (eventTypes != null) {
+            
             for (var i = 0; i < this.eventTypes.length; i++) {
-                // create a listener list for every custom application event
+                this.listeners[ this.eventTypes[i] ] = new Array();
-                this.listeners[ this.eventTypes[i] ] = [];
             }
         }
 
-        for (var i = 0; i < this.BROWSER_EVENTS.length; i++) {
-            var eventType = this.BROWSER_EVENTS[i];
 
-            // every browser event has a corresponding application event 
+        // if a dom element is specified, add a listeners list 
-            // (whether it's listened for or not).
+        // for browser events on the element and register them
-            this.listeners[ eventType ] = [];
+        if (div != null) {
 
-            Event.observe(div, eventType, 
+            for (var i = 0; i < this.BROWSER_EVENTS.length; i++) {
-                this.handleBrowserEvent.bindAsEventListener(this));
+                var eventType = this.BROWSER_EVENTS[i];
+    
+                // every browser event has a corresponding application event 
+                // (whether it's listened for or not).
+                this.listeners[ eventType ] = new Array();
+    
+                // use Prototype to register the event cross-browser
+                Event.observe(div, eventType, 
+                    this.handleBrowserEvent.bindAsEventListener(this));
+            }
+    
+            // disable dragstart in IE so that mousedown/move/up works normally
+            Event.observe(div, "dragstart", Event.stop);
         }
-
-        // disable dragstart in IE so that mousedown/move/up works normally
-        Event.observe(div, "dragstart", Event.stop);
     },
 
     /**