More error trapping

I have the following 4 inputs:

<input class="date_entry_area" name="accrued_al_date_from" type="text" maxlength="10">
<input class="date_entry_area" name="accrued_al_date_to" type="text" maxlength="10">
<input class="time_entry_area" name="accrued_al_time_from" type="text" maxlength="5">
<input class="time_entry_area" name="accrued_al_time_to" type="text" maxlength="5">

The first 2 inputs are for entering Dates. The Second 2 are for entering Time ranges.

So, here is what I would like to somehow do.

1st. Add error trapping that makes sure that information entered in the first 2 inputs is entered in the following format:
mm/dd/yyyy (checking to make sure only numbers are entered and the slashes are there.)

2nd. Add error trapping that makes usre that information entered in the second 2 inputs is entered in the following format:
hh:mm (checking to make sure only numbers are entered and the : is there.)

Also foudn good code for this already.