Viewing all records from a parent table in a child's record

re:I want to have a field 

Do you want to have an embedded report of all the departments on the child record form?

No I am referring to a formula field maybe a javascript function to get all the values from a certain field in the parent table.

Thanks

If you make a dummy table called Get all Departments and add 1 record to it, it will be Record ID# = 1.

The make a relationships to your Departments table based on a formula field with a numeric formula  of 1. 

Then make a Combined text summary field on the relationship and it will give you the first 25 unique values.  Then you can look that up from the Get All Departments table down to any table you need, using that same technique. 

I would also first convert that Combined text summary field on the to a text field like this 
List("\n",
Trim(Part($value,1,";")),
Trim(Part($value,2,";")),
Trim(Part($value,3,";")),
Trim(Part($value,4,";")),
Trim(Part($value,5,";")),
Trim(Part($value,6,";")),
Trim(Part($value,7,";")),
Trim(Part($value,8,";")),
Trim(Part($value,9,";")),
Trim(Part($value,10,";")),
Trim(Part($value,11,";")),
Trim(Part($value,12,";")),
Trim(Part($value,13,";")),
Trim(Part($value,14,";")),
Trim(Part($value,15,";")),
Trim(Part($value,16,";")),
Trim(Part($value,17,";")),
Trim(Part($value,18,";")),
Trim(Part($value,19,";")),
Trim(Part($value,20,";"))
Trim(Part($value,21,";")),
Trim(Part($value,22,";")),
Trim(Part($value,23,";")),
Trim(Part($value,24,";")),
Trim(Part($value,25,";")))