GetItems from Calender between 8-17

Hi am trying to get all my items between selected fromDate and selected ToDate datepicker,

When just getting the date for ex 2014-12-07 08:00 to 2014-12-07 09:00 I get my items between 8 and 17 but when trying to get fromDate -1 setDays and toDate +1 setDays, when i am trying to retrieve the items for selectedfromDate and selectedtoDate and add -1 and +1 it get alls items between the time 8 to 00:00 and not between 8-17 when just taking the the without adding -1 and +1

here is my code, does someone now why it gets like that ?

var fromTime;

var toTime; var listItemCustom; var listItemtoDate; var fromTimeConverted; var toTimeConverted; function checkFreebookingdateTime() {

getListCalender = document.getElementById('CalenderListDrop').value;
spHostUrl = decodeURIComponent(getQueryStringParameter('SPHostUrl'));
context = new SP.ClientContext.get_current();
parentContext = new SP.AppContextSite(context, spHostUrl);
web = parentContext.get_web();
list = web.get_lists().getByTitle(getListCalender);
context.load(list);


                listItemCustom = document.getElementById('datepicker').value;
                var listItemFromTime = document.getElementById('timepicker').value;
                listItemtoDate = document.getElementById('datepickerto').value;
                var listItemToTime = document.getElementById('timepickerTo').value;
                var result = listItemCustom + "T" + listItemFromTime + ":00" + "Z";
                var result2 = listItemtoDate + "T" + listItemToTime + ":00" + "Z";
                fromTime = new Date(result);
                var numberToAddbefore = -1;
                fromTime.setDate(fromTime.getDate() + numberToAddbefore);

                var fromDate08 = "T08:00:00Z";
                fromTimeConverted = fromTime.toJSON().split('T')[0] + fromDate08;
                toTime = new Date(result2);
                var numberToAddafter = 1;
                toTime.setDate(toTime.getDate() + numberToAddafter);

                var toDate17 = "T17:00:00Z";
                toTimeConverted = toTime.toJSON().split('T')[0] + toDate17;

                var camlQuery = new SP.CamlQuery('<View><Query><Where><And><Geq><FieldRef Name=\'EventDate\' /><Value IncludeTimeValue=\'TRUE\' Type=\'DateTime\'>' + fromTimeConverted + '</Value></Geq><Leq><FieldRef Name=\'EndDate\' /><Value IncludeTimeValue=\'TRUE\' Type=\'DateTime\'>' + toTimeConverted + '</Value></Leq></And></Where></Query></View>');
                camlQuery.set_viewXml();


                collListItem = list.getItems(camlQuery);
                context.load(collListItem);


                context.executeQueryAsync(onQuerySucceeded, onQueryFailed);

}

function onQuerySucceeded() {

var dtstartCon = new Date(fromTimeConverted);
var dtEndCon = new Date(toTimeConverted);
var convertUtctoFromtime = new Date(dtstartCon.getTime() + dtstartCon.getTimezoneOffset() * 60 * 1000);
var start = new Date(convertUtctoFromtime);
var convertUtcToTime = new Date(dtEndCon.getTime() + dtEndCon.getTimezoneOffset() * 60 * 1000);
var end = new Date(convertUtcToTime);

var listItemEnumerator = collListItem.getEnumerator();
var bookedTimes= [];
var bookedFreeTimes = [];
while (listItemEnumerator.moveNext()) {
    var oListItem = listItemEnumerator.get_current();


    var eventDate = new Date(oListItem.get_item('EventDate'));
    var endDate = new Date(oListItem.get_item('EndDate'));


    bookedTimes.push([eventDate, endDate]);
}

while (start.getTime() < end.getTime()) {
    var timeFree = true;
    var firstnewDate = (start.setTime(start.getTime()));
    var firstNewDt = new Date(firstnewDate);
    var newDate = start.setTime(start.getTime() + 30 * 60 * 1000);
    start = new Date(newDate);

    for (var i = 0; i < bookedTimes.length; i++) {
        var date = bookedTimes[i][0];
        var date2 = bookedTimes[i][1];
        if (firstNewDt.getTime() != date.getTime() && start.getTime() != date2.getTime()) {



        } else {
            bookedTimes.splice(i, 1); 
            timeFree = false;
            break;
        }
    }