Could be wrong but the long running script is more the browser problem than ebay.
Try clearing cookies and cache by clicking on the Ctrl Shift and Delete keys on your computer
Restart your computer
If that does not help then try another browser like Firefox or Chrome
IE is not supported now for ebay
It sounds as if you are using a computer but if not
If you are using the app then try using just through a browser as the app is not good.
It is trial and error for some of these problems
