Passing data between forms in JavaScript

Question

Firstly no links please I am attaching my code, and here is what I need

I have a webform with a master page, a user control and 3 webforms

In webfrom1 I am loading a user control which have a button and that will load the WebFrom2 where it has a button and a text box. Now on clicking button on the WebForm2 it will open a modal with Webform3 where it has same as webform2. Now when I click on save by entering the data in to text box from web form3 I would like to pass that data to text box available in webform2.

Attaching the code of the same.