fix undefine style

Author: Kai Compagner

src/directives.js

@@ -255,7 +255,7 @@ angularDirective("ng:hide", function(expression, element){
 angularDirective("ng:style", function(expression, element){
   return function(element){
     this.$onEval(function(){
-      element.css(this.$eval(expression));
+      element.css(this.$eval(expression) || {});
     }, element);
   };
 });

test/directivesSpec.js

@@ -174,6 +174,13 @@ describe("directives", function(){
     expect(element.css('color')).toEqual('red');
   });
 
+  it('should silently ignore undefined ng:style', function() {
+    var scope = compile('<div ng:style="myStyle"></div>');
+    scope.$eval();
+    dump(sortedHtml(element));
+    expect(element.hasClass('ng-exception')).toBeFalsy();
+  });
+
   it('should ng:show', function(){
     var scope = compile('<div ng:hide="hide"></div>');
     scope.$eval();