Custom Button from Master Table Info on detail page

I am looking for a custom button from the MasterTable Info to go to another page for an employee. Here is what I got so far

Server:

$data = $pageObject->getMasterRecord();
$result["EmployeeID"]=$data["id"];

also tried

$record = $button->getCurrentRecord();
$result["EmployeeID"]=$record["id"];


Client After:

location.href='documents_list.php?mastertable=AdminEmployee&masterkey1='+result["EmployeeID"];

It gives an error with no error message. So I really don't know what the issue could be.

Thoughts?