Adobe Pro Calculations of drop down menus

[Paul23640165hcxw]

I am trying to create a PDF time sheet.

I can figure out how to create drop down menus with start times and finish times for shifts.

But I cannot figure out how to calculate the time in a shift - start time to finish time.

[Thom Parker]

This question has been asked many times. And there are several ways to perform this calculation. 

Time values are not regular calculations, because the user does not enter a time value, they enter a string value that represents a time. 

You can read the basics about time and date handling here:

https://www.pdfscripting.com/public/Date-and-Time-Handling.cfm

However, since you are using a dropdown for entering the dates, you have a unique opportunity to make life easier for yourself.  You can make the export values of the input dropdowns the actual time values. For example "8:00" is 8 hours after midnight, so make it the value 8.  "14:30" is 12.5 hours after midnight, so make the export value 12.5.

Next, make the Shift Hours field a read only text field. 

Use this custom calculation script:

event.value = this.getField("Finish").value - this.getField("Dropdown7").value;

There are more issues that have to be handled to create a complete solution, but getting the calculation right is the first bit.