Show and Hide fields in pdf Form

If you just want to show fields, you can use the built in action to show/hide fields.

Or if you want a script, you can use something like this as 'On Focus' action of field "column.A.1":

this.getField("column.B.1").display = display.visible;
this.getField("column.C.1").display = display.visible;
this.getField("column.D.1").display = display.visible;
this.getField("column.A.2").display = display.visible;

You can use another script as 'On Blur' action if field is left empty to hide fields.

For another row use script in A2 just change field names.
If you need something else pleace try to describe what exactly you looking for.

What do you mean by show?  The fields are already invisible unless highlighting is turned on. 

Do you mean that you don't want the user to be able to enter data in the other fields in the row, unless text is entered into the first column of the row? 

If so, then a better stategy would be to use a validation script on the first field in each row to test the field for an empty string. 

And yes, the same script can be used for all rows if it is well written. 

Here's an article on showing and hiding fields. The same technique would also work for enabling/disabling the fields using the readonly property.  

https://www.pdfscripting.com/public/Hiding-and-Showing-Form-Fields.cfm