Thanks for the report. There was an error in the javascript error handling of purge_async which is now fixed in stable:11227:151b7d3b2f1b.
In the instances you mention, you should now see an error message in the history 'Unable to purge this dataset': This is because of two possible reasons:
- the setting 'allow_user_dataset_purge' in universe_wsgi.ini is 'False' (or commented out)
- there was an error in the call to purge_async on the server
The 'href="javascript:void(0);"' is a common idiom for creating links/anchors where the logic is handled on the client side. It tells the browser that, although the element has all the other properties of a link, it should not load it like another page and the click event will be handled by javascript on the current page.
In the default branch, the error reporting has been (hopefully) improved to display appropriate messages for failed purging as well as better reporting overall. Sorry for the inconvenience.