When using minified files in Eclipse it can caused errors when there shouldn’t be any. Eclipse complains when using jquery.min.js files. One solution is to ignore the specific file.
Go to : Project->Properties->JavaScript->Include Path->Source-> Excluded Groups
ignore specific files by adding a suitable exclusion pattern e.g. **/jquery*.js
Solution found at bug report 349020 comment 15 via stackoverflow topic ignore errors on a specific file