angularjs 前台如何传值给后台？或者后台传前台！！求大神指点迷津

Question

，我写了两种情况，但是都报错，自己找不出原因
情况1 如下 ：
前台：

     <li ng-click="$scope.getCoachsByExperience(1,3)">1-3年</li>
            <li ng-click="$scope.getCoachsByExperience(3,5)">3-5年</li>
            <li ng-click="$scope.getCoachsByExperience(5,10)">5-10年</li>
            <li ng-click="$scope.getCoachsByExperience(10,40)">10年以上</li>

后台：

  $scope.getCoachsByExperience=(a,b)->
        value=[]
        for coach in coachs
          if coach.Experience >a and coach.Experience<=b
            value.push coach
        $scope.coachs=value
        $scope.totalCount=data.TotalCount

    $scope.getCoachsByExperience(a,b)

    报错：
    ReferenceError: a is not defined
at new <anonymous> (http://localhost:8000/app/main/scripts/coach/coach-list.js:19:34)
at d (http://localhost:8000/scripts/angular/angular.min.js:35:36)
at Object.instantiate (http://localhost:8000/scripts/angular/angular.min.js:35:165)
at http://localhost:8000/scripts/angular/angular.min.js:67:421
at link (http://localhost:8000/scripts/angular-route/angular-route.min.js:7:248)
at J (http://localhost:8000/scripts/angular/angular.min.js:54:373)
at g (http://localhost:8000/scripts/angular/angular.min.js:47:256)
at http://localhost:8000/scripts/angular/angular.min.js:46:377
at http://localhost:8000/scripts/angular/angular.min.js:48:217
at w (http://localhost:8000/scripts/angular/angular.min.js:52:29) <div class="content ng-scope" ng-view="ng-view">

Answer 1

就是说找不到变量a，为什么找不到啊