Tracking time on slide with Veeva Clickstream object using JavaScript

clickstream.js

//First thing: get the product SFID
function prod_callback(result) {
  prod_id_array.push(result);
}
com.veeva.clm.getDataForCurrentObject("KeyMessage", "Product_vod__c", prod_callback);



function track(arr) {

  var prod_id;

  var obj = {
    "Track_Element_Id_vod__c": "undefined",
    "Track_Element_Description_vod__c": "undefined",
    "Usage_Duration_vod__c": 0,
    "Answer_vod__c": "",
    "Usage_Start_Time_vod__c": new Date()
  };

  if (prod_id_array.length > 0) {
    if (prod_id_array[0].success === true) {
      obj["Product_vod__c"] = prod_id_array[0].KeyMessage.Product_vod__c;
    }

  }


  function init_callback(result) {
      data.push(result);
    }
    //init_callback(page);

  com.veeva.clm.createRecord("Call_Clickstream_vod__c", obj, init_callback);

  var pages = data.length;
  //console.log(pages);
  var save = function() {

    var num = 0;

    return setInterval(function() {
      num++;
      //this.tracking_object[name].time = num;
      obj["Track_Element_Id_vod__c"] = arr[0];
      obj["Answer_vod__c"] = arr[0]; //so reps can see their page history on call reports
      obj["Track_Element_Description_vod__c"] = arr[1];
      obj["Usage_Duration_vod__c"] = num;

      function callback(result) {
        update_result[0] = result;
      }

      com.veeva.clm.updateRecord("Call_Clickstream_vod__c", data[pages].Call_Clickstream_vod__c.ID, obj, callback);
      //callback(JSON.stringify(obj));
    }, 1000);
  };

  if (interval.length > 0) {
    clearInterval(interval[0]);
  }

  //wait for the create object to return
  setTimeout(function() {
    interval[0] = save();
  }, 200);


}