added update callback events

Author: liabru

README.md

@@ -23,6 +23,7 @@ See the [jquery.matchHeight.js demo](http://brm.io/jquery-match-height-demo).
 - data attributes API
 - can be removed when needed
 - maintain scroll position correctly
+- callback events
 - tested in IE8+, Chrome, Firefox, Chrome Android
 
 ### Status
@@ -80,6 +81,20 @@ All elements with the same group name will be set to the same height when the pa
 
 Note that `byRow` will be enabled when using the data API, if you don't want this then use the alternative method above.
 
+#### Callback events
+
+Since matchHeight automatically handles updating the layout after certain window events, you can supply functions as global callbacks if you need to be notified:
+
+    $.fn.matchHeight._beforeUpdate = function(event, groups) {
+        // do something before any updates are applied
+    }
+
+    $.fn.matchHeight._afterUpdate = function(event, groups) {
+        // do something after all updates are applied
+    }
+
+Where `event` a jQuery event object (e.g. `load`, `resize`, `orientationchange`) and `groups` is a reference to `$.fn.matchHeight._groups` (see below).
+
 #### Removing
 
 It is possible to remove any matchHeight bindings for a given set of elements like so

jquery.matchHeight-min.js

@@ -109,6 +109,8 @@
     $.fn.matchHeight._groups = [];
     $.fn.matchHeight._throttle = 80;
     $.fn.matchHeight._maintainScroll = false;
+    $.fn.matchHeight._beforeUpdate = null;
+    $.fn.matchHeight._afterUpdate = null;
 
     /*
     *  $.fn.matchHeight._apply
@@ -242,10 +244,16 @@
     *  updates matchHeight on all current groups with their correct options
     */
 
-    var _update = function() {
+    var _update = function(event) {
+        if ($.fn.matchHeight._beforeUpdate)
+            $.fn.matchHeight._beforeUpdate(event, $.fn.matchHeight._groups);
+
         $.each($.fn.matchHeight._groups, function() {
             $.fn.matchHeight._apply(this.elements, this.byRow);
         });
+
+        if ($.fn.matchHeight._afterUpdate)
+            $.fn.matchHeight._afterUpdate(event, $.fn.matchHeight._groups);
     };
 
     $.fn.matchHeight._update = function(throttle, event) {
@@ -261,10 +269,10 @@
 
         // throttle updates
         if (!throttle) {
-            _update();
+            _update(event);
         } else if (_updateTimeout === -1) {
             _updateTimeout = setTimeout(function() {
-                _update();
+                _update(event);
                 _updateTimeout = -1;
             }, $.fn.matchHeight._throttle);
         }
@@ -279,7 +287,7 @@
 
     // update heights on load and resize events
     $(window).bind('load', function(event) {
-        $.fn.matchHeight._update();
+        $.fn.matchHeight._update(false, event);
     });
 
     // throttled update heights on resize events

jquery.matchHeight.js

@@ -40,6 +40,17 @@
                     $('.btn-hidden').click(function() {
                         $('body').removeClass('test-hidden');
                     });
+
+                    // example of update callbacks (uncomment to test)
+                    $.fn.matchHeight._beforeUpdate = function(event, groups) {
+                        //var eventType = event ? event.type + ' event, ' : '';
+                        //console.log("beforeUpdate, " + eventType + groups.length + " groups");
+                    }
+
+                    $.fn.matchHeight._afterUpdate = function(event, groups) {
+                        //var eventType = event ? event.type + ' event, ' : '';
+                        //console.log("afterUpdate, " + eventType + groups.length + " groups");
+                    }
                 });
 
             })();