I have a custom list of "requests" which need to accommodate a required time range for a single date (among other fields), so I added "start" and "end" columns of date and time type. I used designer to create a custom new form and displayed these two fields side by side. With jquery, I hid the textbox and calendar of the "end" field, so the user sees a single textbox and calendar for the date and two sets of time dropdown menus. Whenever the date is changed in the visible date textbox, I push it to the hidden date textbox with jquery.
When I click save, the form is validated and the hidden "end" date textbox loses its value. Why is the value lost and how can I keep it?
As a workaround, I'm sure I could make the "end" column not required and set its date within ItemAdding and ItemUpdating event receivers, but would prefer to resolve this on the client side if possible.