Linked date and Date and Time Formatting

[azissofyanp]

When i using Linked Date, I can select the same date in the second date input but the value not appearing in the second date input

End Date ≥ Start Date (NOT WORKING)
End Date > Start Date ( Working)

And then, how to format the input into
YYYY-MM-DD so it can be submitted to MySQL Database

Moreover how to format time as 24H, and 00:00:00 Format