Fill parent text box from popup
I currently have code that will generate a random input into a text box within the same window upon a button click. Is there a way I can make this code populate a text box on a parent window if the code is contained within a popup? The program I'm using is encrypted with only limited access to template files or else I'd just include the code on the page itself.
Here is my current code:
var SystemID = "";
var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
for (var i = 0; i < 8; i++)
SystemID += possible.charAt(Math.floor(Math.random() * possible.length));