perf(jqLite): implement and use the `empty` method in place of `html(‘’)`

jQuery's elem.html('') is way slower than elem.empty(). As clearing
element contents happens quite often in certain scenarios, switching
to using .empty() provides a significant performance boost when using
Angular with jQuery.

Closes #4457

3 files changed, 3 insertions, 3 deletions

diff --git a/docs/component-spec/annotationsSpec.js b/docs/component-spec/annotationsSpec.js
index a2a78077..60b17d9a 100644
--- a/docs/component-spec/annotationsSpec.js
+++ b/docs/component-spec/annotationsSpec.js
@@ -5,7 +5,7 @@ describe('Docs Annotations', function() {
   var body;
   beforeEach(function() {
     body = angular.element(document.body);
-    body.html('');
+    body.empty();
   });
 
   var normalizeHtml = function(html) {
diff --git a/docs/components/angular-bootstrap/bootstrap-prettify.js b/docs/components/angular-bootstrap/bootstrap-prettify.js
index 43248943..72c136d1 100644
--- a/docs/components/angular-bootstrap/bootstrap-prettify.js
+++ b/docs/components/angular-bootstrap/bootstrap-prettify.js
@@ -28,7 +28,7 @@ function escape(text) {
 function setHtmlIe8SafeWay(element, html) {
   var newElement = angular.element('<pre>' + html + '</pre>');
 
-  element.html('');
+  element.empty();
   element.append(newElement.contents());
   return element;
 }
diff --git a/docs/content/guide/dev_guide.unit-testing.ngdoc b/docs/content/guide/dev_guide.unit-testing.ngdoc
index 9d3d9765..e15edeb7 100644
--- a/docs/content/guide/dev_guide.unit-testing.ngdoc
+++ b/docs/content/guide/dev_guide.unit-testing.ngdoc
@@ -222,7 +222,7 @@ var pc = new PasswordCtrl();
 input.val('abc');
 pc.grade();
 expect(span.text()).toEqual('weak');
-$('body').html('');
+$('body').empty();
 </pre>
 
 In angular the controllers are strictly separated from the DOM manipulation logic and this results in