How to prevent the popup blocker for google API drive picker

Question

I have google drive picker on my html form. However, when I click the button I get the browser message that 'popup is blocked'.

I need for this work without the user having to allow it. Can you please have a look at my code let me know how change it so that will work without the user having to enable popups

Thanks

Here is the code..

---

 <a id="auth-button" class="google-drive-btn"  ng-model="resume" href="#" ng-   click="onGoogleLoad()">Choose from Google Drive</a>

$scope.onGoogleLoad = function () {
    var flag = false;
    $http.post('/api/controllers/googledownload/getClientkey').
    success(function (data, status, header, config) {
        gapi.client.load('drive', 'v2', null);
        gapi.load('auth', { 'callback': onAuthApiLoad });
        gapi.load('picker','1');

        function onAuthApiLoad() {

            window.gapi.auth.authorize({
                'client_id': data.clientID,
                'immediate': flag,
                'scope': ['https://www.googleapis.com/auth/drive']
            }, handleAuthResult);
        }

        function handleAuthResult(authResult) {

            if (authResult && !authResult.error) {

                oauthToken = authResult.access_token;
                createPicker();
            }
            else
            {

                flag = true;
                onAuthApiLoad();

            }
        }


        function createPicker() {
            var picker = new google.picker.PickerBuilder()
                .addView(new google.picker.DocsView())
                .setOAuthToken(oauthToken)
                .setCallback(pickerCallback)
                .build();
            picker.setVisible(true);
        }

        function pickerCallback(data) {
            if (data.action == google.picker.Action.PICKED) {
                $scope.showspinner = true;
                var doc = data.docs[0];
                var fileId = doc.id;
                var request = gapi.client.drive.files.get({
                    'fileId': fileId
                });
                request.execute(function (resp) {
                    var token = gapi.auth.getToken();

                    var fileData = {
                        name: resp.title,
                        link: resp.downloadUrl,
                        accessToken: token.access_token,
                        tokenType: token.token_type,
                        mimeType: resp.mimeType
                    };
                    var jsondata = JSON.stringify({ FileData: fileData });

                    $http.post('/api/controllers/files/CloudDownload', { googleFileData: fileData}).
                    success(function (data, status, headers, config) {
                        onFileUploadSuccess(data);
                    }).
                    error(function (data, status, header, config) {

                        $scope.showspinner = false;

                    });
                });
            }
            else if (data.action == google.picker.Action.CANCEL) {

                $scope.showspinner = false;

            }

        }

    }).
    error(function (data, status, header, config) {
        $scope.showspinner = false;


    });

}