I encountered the same problem and finally found the solution. When we created our site originally, it was for an alternate domain in our list. Example www*altdomain*com. (Yes, periods changed to asterisks so these won’t be real URLs) However, when we finally moved all of our primary web pages, and reset the DNS records accordingly, if we went to www*altdomain*com/blog it would rewrite the URL to www*primarydomain*com/blog.
Except that in our Options | General page in WordPress, we still had www*altdomain*com as the URL.
Once reset to www*primarydomain*com in Options | General, I could delete posts (and have them STAY GONE), add categories, etc. And JavaScript is re-enabled.
Hope that helps someone.
