datetimepicker怎么通过点击事件改变timeFormat

$("#StartTime").datetimepicker({

                            timeFormat:"HH:mm:ss",
                            dateFormat:"yy-mm-dd",
                            stepHour : 1,
                            stepMinute : 1,
                            changeMonth : true,
                            changeYear : true,
                            stepSecond : 1
                    });
                                        
                    $("#StopTime").datetimepicker({
                            timeFormat:"HH:mm:ss",
                            dateFormat:"yy-mm-dd",
                            stepHour : 1,
                            stepMinute : 1,
                            changeMonth : true,
                            changeYear : true,
                            stepSecond : 1
                    });        
                
                    $('#DateFormat').bind('change', function() {
                        var DateFormat = $('#DateFormat').val();
                        var dateformat = 'mm-yy-dd';
                        if (DateFormat == 1) {
                            dateformat = 'yy-mm-dd';
                        } else if (DateFormat == 2) {
                            dateformat = 'dd-mm-yy';
                        } else if (DateFormat == 3) {
                            dateformat = 'mm-dd-yy';
                        }
                        $('#StartTime').datetimepicker("option", "dateFormat", dateformat);
                        $('#StopTime').datetimepicker("option", "dateFormat", dateformat);
                    });
                    
                
                    $('#TimeFormat').bind('change',function(){
                        var TimeFormat=$("#TimeFormat").find("option:selected").val();
                        var timeformat='HH:mm:ss';
                        if(TimeFormat == 1){
                            timeformat='hh:mm:ss';
                        }else if(TimeFormat == 2){
                            timeformat='HH:mm:ss';
                        }
                        alert(timeformat);
                        $('#StartTime').datetimepicker("option","timeFormat", timeformat);
                        $('#StopTime').datetimepicker("option","timeFormat", timeformat);
                        
                        
                    });
                
    dateFormat可以改变，但timeFormat就无法改变。求解答，最好能贴出代码，谢谢。
                    

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如果这控件有获取dateFormat的方法的方法，那么可以这样试一下

var dateFormat = $('#StartTime').datetimepicker("option","dateFormat");
$('#StartTime').datetimepicker("option","dateFormat", dateFormat + timeformat);

先获取dateFormat然后拼一起