How to use javascript code in Wix button?

I already put code on Wix site’s HTML body tag that brings some setup widgets in.
and I want to show these widgets when I click the button.

The code of open it is “companyname.open();”. (it is a code in a company’s manual)

So I add onclick event on a button like this.
and the system says it is not a function.

what should I do?

First, DO NOT INTERACT WITH WIX ELEMENT USING SOMETHING ON HTML! open() wont work as it is OUT OF SCOPE!

Please see Wix Velo Reference https://www.wix.com/velo/reference/$w/button

Using other thing outside of this ref. , I can sure 99% result in error

$w(‘#YOURELEMENTNEEDTOSHOW’).show()

Please user this to show something (unhide)