Angular: Empty Fiddle

http://angularjs.org/

HTML

<script src="http://code.angularjs.org/angular-1.0.1.js"></script>
<div ng-controller="MyCtrl">
    <script type="text/ng-template" id="template1">
        {{symbolsLength()}} {{x1()}} {{x2()}}
    </script>
    <script type="text/ng-template" id="template2">
        static html
    </script>
    <input ng-model="model.symbols" />
    <button ng-click="click()">Change Template</button>
    <hr>
    <ng-include src="model.templateName"></ng-include>
</div>

JavaScript

var myApp = angular.module('myApp', []);

function MyCtrl($scope) {
    $scope.model = {
        symbols: 'три',
        templateName: 'template1',
        calls: 0
    };
    
    $scope.click = function() {
        $scope.model.templateName = ($scope.model.templateName == 'template1') ? 'template2' : 'template1';
    };
    
    var callsNum = 0;
    $scope.symbolsLength = function() {
        console.log('symbolsLength() calls: %d', ++callsNum);
        return $scope.model.symbols.length;  
    };
     $scope.x1 = function() {
         return $scope.symbolsLength()+'x1';
     };
     $scope.x2 = function() {
         return $scope.symbolsLength()+'x2';
     };
}