When you try to save document in SharePoint designer - the JavaScript error started raising.
I found that it occurred after a cumulative update SharePoint 2010 - KB2597132.
The solution to fixed it was -
1.Copying files:
FORM.JS
INIT.JS
CORE.JS
BFORM.JS
OWS.JS
from an environment where it works to : "../LAYOUTS/1033".
2.Reset the IE settings
