fix(ngValue): set value property instead of attr

    in case of input element set value using property instead of attribute
    fixed #13984

Author: m-amr

src/ng/directive/input.js

@@ -1750,24 +1750,33 @@ var CONSTANT_VALUE_REGEXP = /^(true|false|\d+)$/;
     </example>
  */
 var ngValueDirective = function() {
+  //helper function
+  var setElementValue = function(element, attr, value){
+    /**
+     *  input use 'value attribute' as default value if 'value property has no value'
+     *  but once set the 'value property' it will not read value from 'value attribute'
+     *  so we set both the value attribute and property here to avoid this problem.
+     */
+    attr.$set('value', value);
+    element[0].value = value;
+  };
+
   return {
     restrict: 'A',
     priority: 100,
     compile: function(tpl, tplAttr) {
       if (CONSTANT_VALUE_REGEXP.test(tplAttr.ngValue)) {
         return function ngValueConstantLink(scope, elm, attr) {
-          attr.$set('value', scope.$eval(attr.ngValue));
+          var value = scope.$eval(attr.ngValue);
+          setElementValue(elm, attr, value);
         };
       } else {
         return function ngValueLink(scope, elm, attr) {
           scope.$watch(attr.ngValue, function valueWatchAction(value) {
-            attr.$set('value', value);
+            setElementValue(elm, attr, value);
           });
         };
       }
     }
   };
-};
-
-
-
+};

test/ng/directive/inputSpec.js

@@ -3046,6 +3046,23 @@ describe('input', function() {
       expect(inputElm[0].getAttribute('value')).toBe('something');
     });
 
+    it('should update the input "value" property and attribute after change the "value" property', function() {
+      var inputElm = helper.compileInput('<input type="text" ng-value="value">');
+
+      $rootScope.$apply(function() {
+        $rootScope.value = 'something';
+      });
+      expect(inputElm[0].value).toBe('something');
+      expect(inputElm[0].getAttribute('value')).toBe('something');
+
+      helper.changeInputValueTo('newValue');
+
+      $rootScope.$apply(function() {
+        $rootScope.value = 'anotherValue';
+      });
+      expect(inputElm[0].value).toBe('anotherValue');
+      expect(inputElm[0].getAttribute('value')).toBe('anotherValue');
+    });
 
     it('should evaluate and set constant expressions', function() {
       var inputElm = helper.compileInput('<input type="radio" ng-model="selected" ng-value="true">' +