2 instances of mod_wrapper results in duplicate ID

[C-Lodder]

Steps to reproduce the issue

If you have 2 instances of mod_wrapper on 1 page, then there will be 2 iframes with the same ID ('blockrandom').

• Create 2 wrapper modules
• Assign them both to the same page
• Inspect the element and they will have the same ID

When a PR is submitted, they'll also have to update: https://github.com/joomla/joomla-cms/blob/staging/media/com_wrapper/js/iframe-height.js#L4

System information

• Joomla staging

[ghost]

Issue confirmed.

[DrDreave]

When examining the issue I noticed the media/com_wrapper/js/iframe-height.js isn't working properly in today's browsers. Enabling the auto height option in recent versions of Chrome and Firefox on MacOS has no effect.

e.g. Chrome throws:

Uncaught DOMException: Failed to read the 'contentDocument' property from 'HTMLIFrameElement': Blocked a frame with origin "http://joomla-git-sample.local" from accessing a cross-origin frame.
    at HTMLIFrameElement.contentDocumentDesc.get [as contentDocument] (<anonymous>:66:14)
    at iFrameHeight (http://joomla-git-sample.local/media/com_wrapper/js/iframe-height.min.js?84614c47e342ac58508eacfcd3d2d1ec:1:99)
    at HTMLIFrameElement.onload (http://joomla-git-sample.local/wrapper-module:162:19)

I think alternative approaches of setting the height should be discussed before reworking the id assignment to the wrappers.

[brianteeman]

Closed see #19136