In many timesheet-style PDF files you want to have a calculation of the time difference between a starting hour and an ending one. Something like when a worker checks in and then out. With this script you can automatically create the script to calculate that difference. There's also an option to sum up all times to a final piece.

Updates:
This script can now also be used to total an entire column of time expressions to a single result field.
You can now use the script for either 24-hour or 12-hour time notations.You can now also select whether to show the results in decimal notation (so 2 hours and 30 minutes will show as "2.5") or in time notation (so 2 hours and 30 minutes will show as "2:30").
(19/06/2014) : It's no longer necessary to have the fields named with a number starting from 1. You can specify any starting index number (the default is still 1, though).


For example, this is the form we have:

We then run the script and get this window, into which we enter the names of the fields:

The script then runs and applies the calculation scripts:

And the final result is this (the total field is at the bottom-left):

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