s:checkbox fieldValue always true in validation before submitting

I am using Struts 2 <s:checkbox /> in my form processing, along with AngularJS and jQuery. Before submitting, I need validation and until now we do this in the project:

When we press Submit button, this function is called:

$scope.processForm('myForm', '<s:url value="/form/validate.action" />', '<s:url value="/form/save.action" />');

,where processForm(formId, validateUrl, submitUrl) is a funtion defined by us:

$scope.processForm = function(form, validateUrl, submitUrl) {
        window.scroll(0,0);
        ProccessFormService.processStandarForm(form, validateUrl, submitUrl);
    };

And furthermore, we have processStandarForm() defined in a global service:

angular.module('ourApp').controller('myFormCtrl', function($scope, $modal, ProccessFormService) {
...
}

In service:

(function() {

angular.module('ourApp').factory('ProccessFormService', ['$http', function($http) {

    processStandarForm: function(form, validateUrl, submitUrl) {        
            this.processForm(form, validateUrl, submitUrl);
        },

    processForm: function(form, validateUrl, submitUrl, success) {

            if ((typeof form) == 'string') {
                form = document.getElementById(form);
            }

            var data = this.form2Object(form);
            var ctrl = this;

            if (data) {
                if (validateUrl) {
                    $http({
                        method  : 'POST',
                        url     : validateUrl,
                        data    : $.param(data),  // pass in data as strings
                        headers : { 'Content-Type': 'application/x-www-form-urlencoded' }  // set the headers so angular passing info as form data (not request payload)
                    }).success(function() {
                        if (!success) {
                            form.action = submitUrl;
                            form.submit();
                        } else {
                            ctrl.submitAjaxForm(submitUrl, data, success)
                        }
                    });
                } else if (submitUrl) {
                    if (!success) {
                        form.action = submitUrl;
                        form.submit();
                    } else {
                        this.submitAjaxForm(submitUrl, data, success)
                    }
                }
            }       
        },



}

Basically, we are submitting twice the form, firstly for validation, then for submitting.

What I don't understand, is that if I debug in action class, in the function of validate(), the boolean value of <s:checkbox /> is always true, but in submit() function, boolean values are submitted correctly, according to they are checked/not checked. Checkboxs are like this:

<div class="col-sm-12 form-checkbox">
     <s:checkbox name="myForm.married" ng-model="checkboxModel" value="<s:property value='%{myForm.married}'/>"  ng-change="submitCheckbox();" ng-init="checkboxModel= %{myForm.married}" theme="simple"  ng-disabled="anotherFunction()" />
</div>

I understand that, the value submitted is fieldValue="xxx" in <s:checkbox />, and by default is true. So I did this to change the fieldValue of every checkbox before the page is loaded. Although all the script are executed, nothing changed. I still get all true in validation.

$(document).ready(function(){
$( "input:checkbox" ).each(function(){
        var checkbox = $(this);
        var checked = checkbox.prop("checked");//sera false/true
        if (checked == true){
            checkbox.prop("fieldValue", "true");
        } else {
            checkbox.prop("fieldValue", "false");
        }
    });
});

So, how can I get right boolean values not only in submitting, but also in validation?? Is the Angular service wrongly written?? I really doubt that but I am not able to figure out the question. Please help and thanks.