Javascript not working in Chrome and IE

function TimeCheck() {        
    
         var Date1 = new Date(StartTime.get_selectedDate())       
         var date2 = new Date(Date1);
         var date3=date2.setMinutes(date2.getMinutes() + 30);
         var Endtime = new Date(date3);
           document.getElementById('ctl02_ViewEventsOnCalendar1_SchedulerControl_Form_EditEventControl_EndTime_dateInput_display').innerHTML = Endtime.format("M/d/yyyy h:mm tt");
document.getElementById('hfEndTime').value = Endtime.format("M/d/yyyy h:mm tt");
      
     }

<telerik:RadDateTimePicker ID="StartTime"  runat="server" Skin="Office2007" TimeView-EndTime="22:00:00" 
                    TimeView-Interval="00:30:00" TimeView-StartTime="07:00:00" AutoPostBackControl="None"  onchange="javascript:TimeCheck();"
                    
                     önSelectedDateChanged="StartTime_SelectedDateChanged">
                    <TimePopupButton ImageUrl="" HoverImageUrl="" ></TimePopupButton>
                    <TimeView CellSpacing="-1" Culture="English (United Kingdom)"  önClientTimeSelected="OnClientTimeSelected"  >
                    </TimeView>
                    <DateInput AutoPostBack="false" >
                        <ClientEvents OnLoad="onLoadRadTimePicker1"  önValueChanged="validateBackdate" />
                    </DateInput>
                    <Calendar UseRowHeadersAsSelectors="False" UseColumnHeadersAsSelectors="False" ViewSelectorText="x" 
                        Skin="Office2007">
                    </Calendar>
                    <DatePopupButton ImageUrl="" HoverImageUrl="" ></DatePopupButton>
                </telerik:RadDateTimePicker>