directive in module ng  
 Specify custom behavior on focus event. Note: As the focus event is executed synchronously when calling input.focus() AngularJS executes the expression using scope.$evalAsync if the event is fired during an $apply to ensure a consistent state. 
 Directive Info This directive executes at priority level 0. Usage  as attribute: <window, input, select, textarea, a
  ng-focus="expression">
...
</window, input, select, textarea, a>   Arguments Param Type Detail