Button that displays hidden templates does not work in Adobe Reader, but does in Professional

Hi everyone!

I have a perplexing issue and am seeking your fabulous guidance.

Our organisation has Adobe Acrobat Reader DC version 2018.001.20055 installed across all computers, with a few staff using Adobe Professional and Nuance.

I am designing a request form which has 7 pages, 5 of these pages are hidden templates (enabled via using Organise Pages -> Page Templates - set as hidden functionality).  The users only see a 2 page form by default on opening and click a button called 'Buy another item' which adds a new page.  There is Javascript code activated for 'mouse up' events for this 'add new page' button (code shown below):

this.getTemplate("page2").hidden = false;
this.movePage(this.numPages - 1, 0);

this.getField("Itemtype2").setFocus();
this.getField("insertnewpage1").hidden = true;
this.getField("newpagehelp1").hidden = true;

This button/code works on Adobe Professional 2017 but will NOT work using Adobe Reader.  I have tried saving the form with Extended Reader PDF functionality (File -> Save as Other -> Reader Extended PDF -> Enable More Tools, but the button still doesn't work using Adobe Acrobat Reader, but works everytime using Adobe Professional.

Can any kind person out there advise how I can get this button running using Adobe Reader?

Thank you very much in advance 🙂