Rename private attribute _element to _el

Change-Id: I9c7a31bd6844636737ffa6456562b997f5e370a3
diff --git a/dev/js/src/plugin/widget.js b/dev/js/src/plugin/widget.js
index 5f8ca9a..48cc393 100644
--- a/dev/js/src/plugin/widget.js
+++ b/dev/js/src/plugin/widget.js
@@ -32,8 +32,8 @@
     show : function () {
 
       if (this._load) {
-        if (this._element)
-          this._element.classList.add('show');
+        if (this._el)
+          this._el.classList.add('show');
         return this._load;
       }