Angular JS : Does $scope exist without controller -

i have couple of questions in angular. since new angular can please explain below questions

what scope of variable fname on below code if haven't created controller
```
<html>  <body ng-app="">     <input type="text" ng-model="fname" />     <span ng-bind="fname"></span> </body> </html> 
```
as per understanding $scope needed two-way binding. in above scenario $scope exist or not, controller not created. if using $rootscope can able add function alert or console fname value
```
<button ng-click="alertme()">button</button> 
```
where use expression inside angular bultin directive. have seen serveral examples in cases {{}} used inside builtin directive. e.g: ng-form="{{}}" there rule expression in directives

scopes attached dom $scope data property, , can retrieved debugging purposes

the location root scope attached dom defined location of ng-app directive.

scopes allows two-way data binding, can restrict one-way.

regarding {{}}

consider javascript eval() function, when want evaluate expression, should use {{}}. evaluates expression , inserts in html.

WIKI