Merge pull request #65 from ImLiam/patch-1

Add option to disable drag event

README.md

@@ -83,7 +83,7 @@ $('.dd').nestable({
 });
 ```
 
-`onDragStart` callback provided as an option is fired when user starts to drag an element.
+`onDragStart` callback provided as an option is fired when user starts to drag an element. Returning `false` from this callback will disable the dragging.
 ```js
 $('.dd').nestable({
     onDragStart: function(l,e){
@@ -289,6 +289,10 @@ These advanced config options are also available:
 
 ## Change Log
 
+### 16th June 2017
+
+* [imliam] Added support to return `false` from the `onDragStart` event to disable the drag event
+
 ### 28th May 2017
 
 * [pjona] Function `add` support `parent_id` property

jquery.nestable.js

@@ -604,7 +604,11 @@
             position.top = e.pageY;
             position.left = e.pageX;
 
-            this.options.onDragStart.call(this, this.el, dragItem, position);
+            var continueExecution = this.options.onDragStart.call(this, this.el, dragItem, position);
+
+            if (typeof continueExecution !== 'undefined' && continueExecution === false) {
+                return;
+            }
 
             this.placeEl.css('height', dragItem.height());