Edit in JSFiddle

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

myapp.controller('samplecontoller', function ($scope) {

  
    $scope.loading = false ; 
    
    $scope.onSubmit = function(){
        $scope.loading = true ; 
    }
    $scope.cancel = function(){
        $scope.loading = false ; 
    }


});


 

<div ng-app="sampleapp">
<div ng-controller="samplecontoller">
    
    <form  ng-submit="onSubmit()" class="form">
        <p>Click on save button</p>
    <div class="form-actions">
    <button class="btn btn-primary">
        <span data-ng-hide="loading">
            Save 
        </span>
        <span data-ng-show="loading">
            Saving
            <i class="fa fa-spinner fa-spin"></i>
        </span>
    </button>    
    </div>
    </form>
    
    <div class="cancel">
        <p>Click to Cancel</p>
        <button class="btn" ng-click="cancel()">Cancel</button>
    </div>
</div>
</div>

.form{
    padding:20px
}
.cancel{
    
    padding:20px;
}