Resetting Form When modalpop up gets closed if i click any place in my page

I am using Angular 1.3.I have a form in modal Pop-up.After submitting the form my modal Pop-up form is reset and if i click cancel button my form also reset
$scope.add_user = function(add_form)
{
if(add_form.$valid)
{
$http({
method:'POST',
url:file_path,
headers:{'Content_Type':'appliaction/json'},
data:$scope.text
}).success(function(data){
$scope.modalShown_add = ! $scope.modalShown_add;
$scope.modalShown_addsuccess = !$scope.modalShown_addsuccess;
$scope.getlist();
add_form.reset();
}).error(function(data){
add_form.reset();
})
}
}

but when i have any validation error if i click any place of my page my modal Pop-up gets closed after i open the modal Pop-up i am not able to reset my form.Suppose if i pass form name in add function to reset the form i am getting error

$scope.add =function()
{
$scope.modalShown_add = ! $scope.modalShown_add;
}