Returning bool in ajax request

Returning bool in ajax request

Hello All,

I have a common ajax method like the one below, 

function callService(url, data, success, failure) {
   $.ajax({
        url: requestUrl,
        method: "POST",        
        contentType: "application/json; charset=utf-8",
        dataType: 'JSON',
        data: { model: JSON.stringify(model) },
        success: successCall,
        error: failureCall
    });


Now somewhere else, I am using the above method
function getTheData()
{
callService(url, data, newFunction, function (error) { });
}


Now in the newFunction,

function newFunction()
{
//Somefunction which retrurn boolean
if(data.d.length > 0)
return true;
else
return false;
}

In this how I can return boolean variable to callService or getTheData method?

Thanks,
Shannila