Text representation of date and time in their corresponding text box in a control, can be changed using the available API called dateFormat, timeFormat. By default those values will be set based on culture.
To know about standard patterns for date format. Please check with the format section available in DatePicker display format section.
Also like formatting the date value, the time value also can be formatted. Make use of below details, to create your custom time format using timeFormat API.
hh – Hour.
mm – Minutes.
ss – Seconds.
tt - The AM/PM designator.